CN108831879B - Hybrid integrated dual-band multispectral shortwave infrared detector - Google Patents

Abstract

The invention proposes a hybrid integrated dual-spectrum multi-spectral short-wave infrared detector. Along the incident direction of light, a MEMS optical filter or an interference chip is arranged in sequence, and a dual-spectrum multi-spectrum multi-spectrum detector is arranged under the MEMS optical filter or interference chip. Spectral infrared detector unit or array, a signal processing chip or readout circuit chip is arranged under the dual-spectrum multispectral infrared detector unit or array, and the signal processing chip or readout circuit chip completes the detector signal output and the configuration of the working point , and realize MEMS chip power input modulation. The invention realizes dexterous single-chip wide-spectrum multi-spectral detection, and the spectral resolution and modulation flexibility of this multi-spectral detection are far superior to other on-chip integration methods; the signal processing chip or the readout circuit chip is connected with the The hybrid integration of multi-spectral detectors can not only realize the product chip, which is conducive to the development of portable spectral sensing applications, but also can make multi-spectral focal plane image sensors to meet the application requirements of low-cost and smart imaging spectrometers.

Description

Hybrid integrated dual-band multispectral shortwave infrared detector

technical field

The invention belongs to the technical field of semiconductor design and manufacture, relates to the technical field of InP-based III-V compound semiconductor optoelectronic devices, and in particular relates to a hybrid integrated dual-spectrum multispectral short-wave infrared detector with a novel structure

Background technique

"Short-wave infrared" (1.0-2.5μm) spectrum is an important band range for spectral sensing detection and spectral analysis applications. At present, InGaAs and HgCdTe are the most mainstream detector technologies in this spectral range. Among them, the InGaAs detector is based on the mature InP-based III-V compound semiconductor technology. It not only has the best performance in the 1.7μm response cutoff spectrum, but also has a sensitivity comparable to HgCdTe in the 1.7-2.5μm range. At present, when the cutoff wavelength is extended to 2.5μm, due to the limitation of the detector structure, the response of the monolithic InGaAs detector can only effectively cover the spectral range of 1.3-2.5μm, and the standard response wavelength (0.9-1.7μm) matched with the lattice Compared with the InGaAs detector, the detection sensitivity within 1.7 μm is relatively low due to the significantly increased dark current. In multi-spectral applications, it is of great significance to expand the spectral range and improve the sensitivity of the response spectrum. How to improve the detection sensitivity below the wavelength of 1.7 μm is a technical problem that needs to be solved urgently.

SUMMARY OF THE INVENTION

The invention aims to solve the technical problems existing in the prior art, and particularly innovatively proposes a hybrid integrated dual-spectrum multispectral short-wave infrared detector.

In order to achieve the above purpose of the present invention, the present invention provides a hybrid integrated dual-spectrum multispectral short-wave infrared detector, which is sequentially provided with:

MEMS optical filter or interference chip, electrodes are formed on the MEMS optical filter or interference chip;

A dual-spectral multi-spectral infrared detector unit or array is arranged under the MEMS optical filter or interference chip, and the dual-spectral multi-spectral infrared detector is connected with the MEMS optical filter or interference chip by mounting or coupling;

A signal processing chip or a readout circuit chip is arranged under the dual-spectral multispectral infrared detector unit or array, and the dual-spectral multispectral infrared detector and the signal processing chip or the readout circuit chip are bonded by wire bonding or flip-chip connection, and the part of the signal processing chip or the readout circuit chip is exposed and formed with electrodes;

The electrodes of the MEMS optical filter or interference chip and the electrodes of the signal processing chip or the readout circuit chip are interconnected by wires;

The backside of the signal processing chip or the readout circuit chip is the data and power interface.

The micro-assembly and integration of the MEMS optical filter or interference chip and the dual-spectral multi-spectral infrared detector of the invention realizes a flexible single-chip wide-spectrum multi-spectral detection. Compared with other dual multi-color detectors, such as filtering Optical window filtering, on-chip integrated microstructure dielectric film filtering, REC resonant detectors, etc., the spectral resolution and modulation flexibility of this multispectral detection have been significantly improved.

The hybrid integration of ASICs or ROIC special IC chips and multi-spectral detectors of the present invention can not only realize the product chip, which is conducive to the development of portable spectral sensing applications, but also can produce multi-spectral focal plane image sensors, which can meet the requirements of low-cost, smart imaging spectrometers application requirements.

In a preferred embodiment of the present invention, the dual-band multi-spectral infrared detector includes:

InP substrate;

InP of the first conductivity type is formed on the InP substrate as a lower contact layer of the first absorption layer structure;

Intrinsic In _x1 Ga _1-x1 As is formed on the lower contact layer of the first absorption layer structure as a first absorption layer, wherein 0<x1<1, the first absorption layer covers part of the lower contact layer , the first absorption layer is preferably In _0.53 Ga _0.47 As;

InP of the second conductivity type is formed on the first absorption layer as a common contact layer;

A lattice adaptation buffer layer is formed on the common contact layer, the bottom layer of the lattice adaptation buffer layer is lattice matched with the common contact layer, the upper layer is lattice matched with the second absorption layer, and the lattice adaptation buffer layer is lattice matched with the second absorption layer. The buffer layer covers part of the common contact layer;

An intrinsic or first conductive type In _x2 Ga _1-x2 As is formed on the lattice adaptation buffer layer as a second absorption layer, wherein 0<x2<1, x2>x1;

A first conductive type In _x3 Al _1-x3 As upper contact layer is formed on the second absorption layer, wherein 0<x3<1; and x2-0.1<x3<x2+0.1;

Electrodes are formed on the lower contact layer, the exposed portion of the common contact layer and the upper contact layer.

The present invention adopts the design scheme of two-color detector, combines the standard wavelength response PIN detector (PD1) and the extended wavelength response PIN detector (PD2), uses PD1 to respond to the spectrum below 1.7 μm, and uses PD2 to respond to the 1.7-2.5 μm spectrum . PD1 and PD2 share the P electrode to form a back-incidence n-i-p-i-n type device structure, and the modulation of the response spectrum is realized by switching the electrode bias.

The invention greatly improves the quantum efficiency of the spectral band below 1.7 μm, significantly reduces the dark current, and significantly improves the detection sensitivity.

According to the distribution characteristics of the spectral signal, the spectral range below 1.7 μm is mainly based on light reflection detection, and the spectral range of 1.7-2.5 μm is mainly based on thermal radiation detection. Two-color detection requirements for some specific applications, flexible application.

In a preferred embodiment of the present invention, an etching barrier layer, preferably In _0.53 Ga _0.47 As, is formed between the InP substrate and the lower contact layer. The invention can effectively expand the spectral response range of the InGaAs detector, and the working wavelength covers a wide spectral range of 0.95-2.5 μm. If the InP substrate is completely peeled off, the working wavelength will effectively cover the near-infrared-short-wave infrared wide spectrum of 0.75-2.5 μm. The widest response spectrum can cover the visible short-wave spectrum range of 0.4-2.5μm.

In another preferred embodiment of the present invention, the first conductivity type is N type, the second conductivity type is P type, and the conductivity type of the lattice adaptation buffer layer is P type, preferably Be doped. Be doping is more conducive to improving the epitaxial crystal quality of the buffer layer, helping to improve the epitaxial quality of the second absorption layer, and improving the response sensitivity of the extended wavelength.

In another preferred embodiment of the present invention, the lattice adaptation buffer layer is a multi-layer structure, using InAlAs or InAsP material with a linear composition gradient or composition gradient gradient, through composition modulation, the bottom layer and the common contact layer crystal The upper layer is lattice matched with the second absorber layer. The epitaxial growth quality of the second absorber layer is improved.

In another preferred embodiment of the present invention, the dual-band multi-spectral infrared detector includes:

substrate;

The first absorber layer structure, the second absorber layer structure, ..., the ith absorber layer structure, ..., the Nth absorber layer structure are sequentially formed on the substrate from bottom to top, where N is a positive value greater than 1 Integer, the i is a positive integer greater than 1 and less than or equal to N;

Each absorption layer structure has a lower contact layer, an absorption layer and an upper contact layer, and the contact layers of the adjacent two absorption layer structures are shared;

In the upward direction from the substrate, the absorption wavelengths of the N absorption layers gradually become longer.

The invention adopts a multi-color detector structure design, and can realize multi-color synchronous detection in a wide spectral range.

In a preferred embodiment of the present invention, an etch barrier layer is formed between the substrate and the first absorber layer structure. By setting the corrosion barrier layer, the substrate can be completely peeled off, the detectable spectral range is widened, and the visible light band is expanded.

In another preferred embodiment of the present invention, a filter layer is formed between two adjacent absorption layer structures, and the absorption wavelength of the filter layer is between the absorption wavelengths of the two absorption layer structures in contact with the filter layer. The degree of freedom of modulation in the detection spectrum range is greatly increased, and narrow-band-pass multicolor detection can be realized.

In another preferred embodiment of the present invention, N is 2.

In another preferred embodiment of the present invention, the dual-band multi-spectral infrared detector includes:

InP substrate; InP of the first conductivity type is formed on the InP substrate as the lower contact layer of the first absorption layer structure; intrinsic _Inx4 is formed on the lower contact layer of the first absorption layer structure Ga _1-x4 As _y4 P _1-y4 as the first absorption layer, wherein 0<x4<1, 0<y4<1 and y4=2.2×(1-x4), the first absorption layer covers part of the lower contact layer; InP of the second conductivity type is formed on the first absorption layer as a common contact layer; Intrinsic Inx5 Ga _{1-x5 As y5} P _1-y5 or In is formed on the common contact layer _x6 Ga _1-x6 As is used as the second absorber layer, wherein 0<x5<1, 0<y5<1 and y5=2.2×(1-x5); x4<x5;0.53<x6<0.6; the second The absorption layer covers part of the common contact layer and is lattice-matched with InP; InP of the first conductivity type is formed on the second absorption layer as an upper contact layer; on the exposed part of the lower contact layer and the common contact layer and electrodes are formed on the upper contact layer.

The invention adopts the structure design of the dual-color detector and utilizes the band gap adjustment of the In _x Ga _1-x As _y P _1-y absorption layer to realize dual-color detection in the spectral range of 0.95-1.7 μm, and the dual-chromatic range can be continuously modulated .

In another preferred embodiment of the present invention, an etching barrier layer (preferably In _0.53 Ga _0.47 As) is formed between the InP substrate and the lower contact layer. The etch barrier layer is provided to facilitate the peeling of the InP substrate. If the InP substrate is completely peeled off, the operating wavelength will effectively cover a wide spectral range of 0.6-1.7 μm. Expanded detectable spectral range.

In another preferred embodiment of the present invention, the structure of the common contact layer is replaced by the following structure: a first electron barrier layer of InP of the second conductivity type is formed on the first absorption layer, and the first electron barrier layer of the second conductivity type is formed on the first absorption layer. The barrier layer is formed with a second conductive type In _x7 Ga _1-x7 As _y7 P _1-y7 filter layer on top, wherein 0<x7<1, 0<y7<1 and y7=2.2×(1-x7); x4<x7<x5; an InP second electron barrier layer of the second conductivity type is formed on top of the filter layer, the second electron barrier layer covers part of the filter layer, and the lower contact layer and the filter layer are exposed Electrodes are formed on portions and the upper contact layer.

The invention inserts the p-InGaAsP filter layer as the common contact layer, which not only greatly increases the degree of freedom of modulation of the spectral range of the two-color detection, but also realizes the narrow-band-pass two-color detection. It is beneficial to reduce the dark current of the detector. The detector structure designed by the invention not only satisfies the requirements of dual-color wide-spectrum detection, but also can meet the narrow-band-pass dual-color detection requirements of some specific spectral identification applications, and is flexible in application.

In another preferred embodiment of the present invention, in the dual-band multi-spectral infrared detector:

The thickness of the first absorption layer is 2.0-3.5 μm, and the cut-off wavelength of the band gap is λ _C1 ;

The thickness of the second absorption layer is 2.0-3.5μm, the band gap cut-off wavelength λ _C2 ≤1.7μm,

The thickness of the filter layer is 2.0 μm-3.5 μm, and the band gap cut-off wavelength λ _C1 ≤λ _CF ≤λ _C2 .

Prevent the signal to be detected from being absorbed by the absorbing layer that passes through first, and ensure the detection effect.

Additional aspects and advantages of the present invention will be set forth, in part, from the following description, and in part will be apparent from the following description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

1 is a schematic diagram of the spectral response at room temperature after the substrate is completely peeled off in a preferred embodiment of the present invention (Structure 1);

FIG. 2 is a schematic diagram of the spectral response at room temperature when the substrate is not peeled off in a preferred embodiment of the present invention (structure 1).

3 is a schematic structural diagram of a dual-spectral multi-spectral infrared detector in another preferred embodiment of the present invention;

FIG. 4 is a schematic diagram of the spectral response at room temperature after the structural substrate shown in FIG. 3 is completely peeled off;

FIG. 5 is a schematic diagram of the spectral response at room temperature of the structural substrate shown in FIG. 3 without stripping;

6 is a schematic structural diagram of a dual-spectral multi-spectral infrared detector in a third preferred embodiment of the present invention;

FIG. 7 is a schematic view of the spectral response at room temperature of the structural substrate shown in FIG. 6 without stripping;

FIG. 8 is a schematic structural diagram of a hybrid integrated dual-spectrum multispectral short-wave infrared detector of the present invention.

Detailed ways

The following describes in detail the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, only used to explain the present invention, and should not be construed as a limitation of the present invention.

In the description of the present invention, it should be understood that the terms "portrait", "horizontal", "upper", "lower", "front", "rear", "left", "right", "vertical", The orientations or positional relationships indicated by "horizontal", "top", "bottom", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than An indication or implication that the referred device or element must have a particular orientation, be constructed and operate in a particular orientation, is not to be construed as a limitation of the invention.

In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it may be a mechanical connection or an electrical connection, or two The internal communication between the elements may be directly connected or indirectly connected through an intermediate medium, and those of ordinary skill in the art can understand the specific meanings of the above terms according to specific circumstances.

The present invention provides a hybrid integrated dual-spectrum multispectral short-wave infrared detector, as shown in FIG. 8 , which is sequentially arranged along the direction of light incidence:

MEMS (Micro-Electro-Mechanical System, Micro-Electro-Mechanical System) optical filter or interference chip, electrodes are formed on the MEMS optical filter or interference chip; in this embodiment, the MEMS optical filter chip can adopt the existing structure Fabry-Perot tunable filter MEMS chip, MEMS interference chip can use the existing Michelson optical interference chip. The specific MEMS optical filter or interference chip can be fabricated by silicon-based, germanium-based or gallium-arsenide-based technology.

A dual-spectral multi-spectral infrared detector unit or array is arranged under the MEMS optical filter or interference chip, and the dual-spectral multi-spectral infrared detector and the MEMS optical filter or interference chip are mounted by optical structural adhesive or optical They are connected in a coupling manner, and the specific process can adopt the existing technology.

A signal processing chip or a readout circuit chip is arranged under the dual-spectral multispectral infrared detector unit or array, and the dual-spectral multispectral infrared detector and the signal processing chip or the readout circuit chip are bonded by wire bonding or flip-chip connection, the signal processing chip or the readout circuit chip is partially exposed and formed with electrodes.

The electrodes of the MEMS optical filtering or interference chip and the electrodes of the signal processing chip or the readout circuit chip are interconnected by wires; the electrical interconnection is realized by wire bonding, and the power supply bias of the MEMS chip is modulated. The specific MEMS optical filter or interference chip preferably adopts the existing structure based on silicon.

Specifically, an ASICs signal processing chip/ROIC readout circuit chip can be used. The ASICs (Application Specific Integrated Circuit, application specific integrated circuit) signal processing chip/ROIC (Readout Integrated Circuit, readout circuit) readout circuit chip has a detector signal output port and MEMS chip power input modulation port. In this embodiment, the ASIC chip mainly includes functional circuit units such as bias power supply, transimpedance amplifier, ADC, register, data interface, etc.; ROIC adopts CTIA type pixel readout circuit structure, and the specific circuit structure design is related to the impedance and capacitance of the detector. resistance characteristics to match.

The invention provides a dual-spectrum multi-spectral infrared detector to solve the problems of low quantum efficiency in the short-wave direction and narrow spectral response range in the current extended short-wave infrared InGaAs detector, and can significantly improve the wavelength below 1.7 μm detection sensitivity.

In this embodiment, the dual-band multi-spectral infrared detector includes a substrate, and any semiconductor substrate can be selected, which can be, but is not limited to, a general-purpose group IV, group III-V, group II-VI semiconductor substrate. , or a sapphire substrate, such as an InP substrate. It also includes the first absorption layer structure, the second absorption layer structure, ..., the i-th absorption layer formed sequentially on the substrate from bottom to top (the direction from the substrate to the epitaxial measurement layer is set as the direction from bottom to top) Structure, ..., Nth absorbing layer structure, the N is a positive integer greater than 1, and the i is a positive integer greater than 1 and less than or equal to N. The preferred N is 2. Each absorption layer structure has a lower contact layer, an absorption layer and an upper contact layer, and the contact layers of two adjacent absorption layer structures are shared. Along the upward direction from the substrate, the absorption wavelengths of the N absorption layers gradually become longer. .

In a preferred embodiment of the present invention, a dual-spectral multi-spectral infrared detector includes:

InP substrate;

InP of the first conductivity type is formed on the InP substrate as a lower contact layer of the first absorption layer structure;

Intrinsic In _x1 Ga _1-x1 As is formed on the lower contact layer of the first absorption layer structure as a first absorption layer, wherein 0<x1<1, the first absorption layer covers part of the lower contact layer , the first absorption layer is preferably In _0.53 Ga _0.47 As;

InP of the second conductivity type is formed on the first absorption layer as a common contact layer;

A lattice adaptation buffer layer is formed on the common contact layer, the bottom layer of the lattice adaptation buffer layer is lattice matched with the common contact layer, the upper layer is lattice matched with the second absorption layer, and the lattice adaptation buffer layer is lattice matched with the second absorption layer. The buffer layer covers part of the common contact layer;

An intrinsic or first conductive type In _x2 Ga _1-x2 As is formed on the lattice adaptation buffer layer as a second absorption layer, wherein 0<x2<1, x2>x1;

A first conductive type _{Inx3Al1 -} x3As upper contact layer is formed on the second absorption layer, wherein 0<x3<1, and x2-0.1<x3<x2+0.1;

Electrodes are formed on the lower contact layer, the exposed portion of the common contact layer and the upper contact layer.

In a preferred embodiment of the present invention, the specific component selection and preparation process are:

Using MOCVD or MBE epitaxy technology, the p-on-n-type PD1 structure and the n-on-p-type PD2 structure layer are sequentially grown on the InP single crystal substrate. The InP substrate material adopts Fe-doped I-type semi-insulating substrate or S-doped N-type substrate;

First, grow the N ⁺ -InP lower contact layer on the InP single crystal substrate. The thickness of the N ⁺ -InP lower contact layer is 0.2μm-1.0μm, the doping concentration is ≥2E+18cm ^-3 , and the donor impurity is Si; if necessary When the InP substrate is peeled off to expand the response spectrum, a layer of In _0.53 Ga _0.47 As etching barrier is inserted between the N ⁺ -InP lower contact layer and the InP substrate. If the substrate needs to be peeled off, the etch barrier layer is provided; if the substrate is not peeled off, the etch barrier layer does not need to be provided.

An intrinsic i-In _0.53 Ga _0.47 As first absorber layer is epitaxially grown on the N ⁺ -InP lower contact layer with a thickness of 2.0-3.5 μm and a background carrier concentration ≤ 1E+15 cm ^-3 .

A p-InP common contact layer is grown on the first absorption layer, the thickness is 0.5μm-1.0μm, the effective doping concentration is ≥1E+18cm ^-3 , and the acceptor impurity is Zn.

A lattice-adapted buffer layer is epitaxially grown on the p-InP common contact layer, and the multi-layer structure of the lattice-adapted buffer layer adopts the linearly graded or compositionally graded InAlAs or InAsP material. The bottom layer is lattice-matched with the p_InP common contact layer, and the upper layer is lattice-matched with the N ^- -In _x Ga _1-x As second absorber layer, the epitaxial thickness is 1-10μm, the effective doping concentration is ≥ 1E+18cm ^-3 , the acceptor Impurities are Zn or Be.

The extended wavelength detector adopts an n-on-p structure, so that the p-type lattice adaptation buffer layer can be doped with Be. Compared with the Si doping of the n-type buffer layer, Be doping is more conducive to improving the epitaxy of the buffer layer. The crystal quality helps to improve the epitaxial quality of the second absorption layer and improve the response sensitivity of the extended wavelength.

A second absorption layer of N ^- -In _x2 Ga _1-x2 As is epitaxially grown on the lattice adaptation buffer layer, the In composition of the second absorption layer is 0.53<x2<0.83, and the maximum band gap absorption cut-off wavelength is 2.6μm (Under refrigeration and low temperature working conditions, the cut-off wavelength is guaranteed not to be less than 2.5μm), the epitaxial thickness is 1.5-2.5μm, the doping concentration is 1-5E+16cm ^-3 , and the donor impurity is Si.

Epitaxial growth of N ⁺ -In _x3 Al _1-x3 As on the second absorber layer on the contact top layer, the In composition of the top contact layer is the same as the second absorber layer (ie x2=x3), the thickness is 0.2-1.0μm, doped The impurity concentration is ≥1E+18cm ^-3 , and the donor impurity is Si.

The detector device is fabricated by mesa technology, and the device mesa is formed by dry etching or wet etching; the device mesa is passivated with SiN _x or Al ₂ O ₃ dielectric film; the exposed part of the lower contact layer, the exposed part of the common contact layer and the upper contact An electrode (light to be measured is incident from the substrate) is formed on the layer. The upper and lower electrodes and the common electrode are made of Cr/Au double-layer metal or Ti/Pt/Au multilayer metal.

If the short-wavelength response wavelength range of PD1 needs to be expanded, selective wet etching is used to peel off the InP substrate.

The invention adopts the structure design of two-color detector, which can effectively expand the spectral response range of the InGaAs detector, and the working wavelength covers a wide spectral range of 0.95-2.5 μm, as shown in Figure 2; if the InP substrate is completely peeled off, the working wavelength will be effective. Covering a wide spectral range of near-infrared-short-wave infrared from 0.75-2.5 μm, as shown in Figure 1.

In another preferred embodiment of the present invention, as shown in FIG. 3 (the figure only schematically shows the dimensions of each area, and the specific dimensions can be designed according to the requirements of device parameters), the present invention provides a dual The spectral-band multi-spectral infrared detector, based on the energy band modulation principle of the InP/InGaAs(P) material system, solves the problems of multi-chip structure and single/dual color detection selection and regulation that exist in the current similar detectors. The dual-band multispectral infrared detector includes:

InP substrate;

A first conductive type (preferably N-type) InP is formed on the InP substrate as a lower contact layer of the first absorption layer structure;

Intrinsic In _x4 Ga _1-x4 As _y4 P _1-y4 is formed on the lower contact layer of the first absorber layer structure as a first absorber layer, wherein 0<x4<1, 0<y4<1 and y4=2.2×(1-x4), the first absorption layer covers part of the lower contact layer;

InP of the second conductivity type is formed on the first absorption layer as a common contact layer;

Intrinsic In _x5 Ga _1-x5 As _y5 P _1-y5 or In _x6 Ga _1-x6 As is formed on the common contact layer as a second absorber layer, wherein 0<x5<1,0<y5< 1 and y5=2.2×(1-x5); x4<x5;0.53<x6<0.6; the second absorption layer covers part of the common contact layer and is lattice-matched to InP;

An InP of the first conductivity type is formed on the second absorption layer as an upper contact layer;

Electrodes are formed on the lower contact layer, the exposed portion of the common contact layer and the upper contact layer.

In this embodiment, an In _0.53 Ga _0.47 As etch stop layer may be formed between the InP substrate and the lower contact layer.

In another preferred embodiment of the present invention, as shown in FIG. 6 , the structure of the common contact layer is replaced by the following structure:

A first electron barrier layer of InP of the second conductivity type is formed on the first absorption layer, and _Inx7 Ga _1-x7 As _y7 P ₁ of the second conductivity type is formed on the first electron barrier layer _-y7 filter layer, wherein 0<x7<1, 0<y7<1 and y7=2.2×(1-x7); x4<x7<x5; an InP layer of the second conductivity type is formed on the filter layer Two electron barrier layers, the second electron barrier layer covers part of the filter layer, and electrodes are formed on the lower contact layer, the exposed part of the filter layer and the upper contact layer.

The invention combines the short-wave wavelength responsive PIN detector (PD1) with the long-wave wavelength responsive PIN detector (PD2), PD1 adopts p-on-n structure, PD2 adopts n-on-p structure, PD1 and PD2 share P electrode, A back-incidence n-i-p-i-n type device structure is formed, and the modulation of the response spectrum is realized by switching the electrode bias. As shown in Figure 6, the design scheme of dual-color detection + on-chip filtering is adopted, and a p-InGaAsP filter layer (common contact layer) is inserted between the short-wave wavelength responsive PIN detector (PD1) and the long-wave wavelength responsive PIN detector (PD2). The continuous modulation of the dual-color detection spectrum is realized.

In a preferred embodiment of the present invention, the specific component selection and preparation process are:

Using MOCVD or MBE epitaxy technology, the p-on-n-type PD1 structure and the n-on-p-type PD2 structure layer are sequentially grown on the InP single crystal substrate. The InP substrate material adopts Fe-doped I-type semi-insulating substrate or S-doped N-type substrate.

First, the N ⁺ -InP lower contact layer is grown on the InP single crystal substrate, the thickness of the N ⁺ -InP lower contact layer is 0.2μm-1.0μm, the doping concentration is ≥2E+18cm ^-3 , and the donor impurity is Si. In a more preferred embodiment of the present invention, if the InP substrate needs to be peeled off to expand the response spectrum, an In _0.53 Ga _0.47 As etching barrier layer is inserted between the N ⁺ -InP lower contact layer and the InP substrate.

Growth of intrinsic i-In _x1 Ga _1-x1 As _y1 P _1-y1 first absorber layer on top of the N ⁺ -InP lower contact layer, the thickness of the first absorber layer is 2.0-3.5 μm, the background carrier concentration ≤ 1E+16cm ^-3 , the band gap cutoff wavelength is λ _C1 .

As shown in FIG. 3 , a p-InP common contact layer is grown on the first absorber layer with a thickness of 0.5 μm-1.0 μm, an effective doping concentration ≥ 1E+18 cm ^-3 , and the acceptor impurity is Zn or Be.

As shown in Figure 4, a p-InP first electron barrier layer is grown on the first absorber layer, the thickness is 0.5μm-1.0μm, the effective doping concentration is ≥1E+18cm ^-3 , and the acceptor impurity is Zn or Be. A p-In _x4 Ga _{1- x4} As _y4 P _1-y4 common contact layer/filter layer is grown on the first electron barrier layer, the thickness is 2.0μm～3.5μm, the effective doping concentration is ≥1E+18cm ^-3 , The acceptor impurity is Zn or Be; the band gap cut-off wavelength λ _C1 ≤λ _CF ≤λ _C2 . A p-InP second electron barrier layer is grown on the common contact layer/filter layer, the thickness is 0.5μm-1.0μm, the effective doping concentration is ≥1E+18cm ^-3 , and the acceptor impurity is Zn or Be.

Growth of an intrinsic i- _{Inx2Ga1 -} x2Asy2P1 _{-y2 second} absorber layer on top of p-InP with a thickness of 2.0-3.5μm, background carrier concentration ≤1E+16cm ^-3 , band gap Cut-off wavelength λ _C2 ≤ 1.7 μm. N ⁺ -InP is grown on the second absorber layer with a thickness of 0.2-1.0 μm, a doping concentration of ≥1E+18 cm ^-3 , and Si as a donor impurity.

The detector device is fabricated by mesa technology, and the device mesa is formed by dry etching or wet etching; the device mesa is passivated with SiN _x or Al ₂ O ₃ dielectric film; the exposed part of the lower contact layer, the exposed part of the common contact layer and the upper contact Electrodes are formed on the layer (as in FIG. 3 ), or electrodes are formed on the lower contact layer, the exposed portion of the filter layer, and the upper contact layer (as in FIG. 6 ). The upper and lower electrodes and the common electrode are made of Cr/Au double-layer metal or Ti/Pt/Au multilayer metal.

If the short-wavelength response wavelength range of PD1 needs to be expanded, selective wet etching is used to peel off the InP substrate.

The invention adopts the structure design of the dual-color detector and utilizes the band gap adjustment of the In _x Ga _1-x As _y P _1-y absorption layer to realize dual-color detection in the spectral range of 0.95-1.7 μm, and the dual-chromatic range can be continuously modulated , as shown in Figure 5; if the InP substrate is completely peeled off, the operating wavelength will effectively cover a wide spectral range of 0.6–1.7 μm, as shown in Figure 4. Inserting the p-InGaAsP filter layer as a common contact layer not only greatly increases the degree of freedom of modulation in the spectral range of the dual-color detection, but also enables narrow-band-pass dual-color detection, as shown in Figure 7. Moreover, using p-InP with a wide band gap as the electron barrier layer is beneficial to reduce the dark current of the detector.

In the invention, the detector device is fabricated by the mesa technology, and the device mesa is formed by dry etching or wet etching; the device mesa is passivated with SiNx or Al ₂ O ₃ dielectric film; the upper and lower electrodes and the common electrode are made of Cr/Au double-layer metal or Ti/Pt/Au multilayer metal.

It should be noted that the incident directions of light in Figs. 3, 6 and 8 are different, and the hierarchical description of the structure in the present invention is carried out in the incident direction of light. Enter the device in the direction of the light rays shown in Figure 8.

In the description of this specification, reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., means a specific feature described in connection with the embodiment or example, A structure, material, or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, The scope of the invention is defined by the claims and their equivalents.

Claims (10)

1. A hybrid integrated double-spectrum multispectral short-wave infrared detector is characterized in that the infrared detector is sequentially arranged along the incident direction of light rays:

a MEMS optical filtering or interference chip on which an electrode is formed;

a dual-spectrum multispectral infrared detector unit or array is arranged below the MEMS optical filtering or interference chip, and the dual-spectrum multispectral infrared detector is connected with the MEMS optical filtering or interference chip in a mounting or coupling mode;

a signal processing chip or a reading circuit chip is arranged below the dual-spectrum multispectral infrared detector unit or array, the dual-spectrum multispectral infrared detector is connected with the signal processing chip or the reading circuit chip in a lead bonding or flip-chip welding mode, and part of the signal processing chip or the reading circuit chip is exposed to form an electrode;

the electrodes of the MEMS optical filtering or interference chip and the electrodes of the signal processing chip or the reading circuit chip are interconnected through leads;

the signal processing chip or the reading circuit chip is provided with a detector signal output port and an MEMS chip power supply input modulation port.

2. The hybrid integrated multispectral shortwave infrared detector of claim 1, wherein the multispectral shortwave infrared detector comprises:

a substrate;

the absorption structure comprises a first absorption layer structure, a second absorption layer structure, … …, an ith absorption layer structure, … … and an Nth absorption layer structure which are sequentially formed on the substrate from bottom to top, wherein N is a positive integer larger than 1, and i is a positive integer larger than 1 and smaller than or equal to N;

each absorption layer structure is provided with a lower contact layer, an absorption layer and an upper contact layer, and the contact layers of two adjacent absorption layer structures are shared;

the absorption wavelengths of the N absorption layers become longer gradually along the incident direction of the light.

3. The hybrid integrated multispectral shortwave infrared detector of claim 1 or 2, wherein the multispectral shortwave infrared detector comprises one of the following structures:

the structure I is as follows:

an InP substrate;

forming InP of a first conductivity type as a lower contact layer of a first absorption layer structure on the InP substrate;

intrinsic In is formed on the lower contact layer of the first absorption layer structure_x1Ga_1-x1As As the first absorption layer, wherein 0<x1<1, the first absorbent layer covers part of the lower contact layer;

InP of a second conductivity type is formed as a common contact layer over the first absorption layer;

a lattice-adapted buffer layer is formed on the common contact layer, the bottom layer of the lattice-adapted buffer layer is lattice-matched with the common contact layer, the upper layer of the lattice-adapted buffer layer is lattice-matched with the second absorption layer, and the lattice-adapted buffer layer covers part of the common contact layer;

forming In of intrinsic or first conductive type on the lattice-adapted buffer layer_x2Ga_1-x2As As the second absorption layer, wherein 0<x2<1，x2>x1；

Forming In of a first conductivity type over the second absorption layer_x3Al_1-x3An upper contact layer of As, wherein 0<x3<1, and x2-0.1<x3<x2+0.1；

Forming electrodes on the lower contact layer, the exposed portion of the common contact layer and the upper contact layer;

the structure II is as follows:

an InP substrate;

forming InP of a first conductivity type as a lower contact layer of a first absorption layer structure on the InP substrate;

intrinsic In is formed on the lower contact layer of the first absorption layer structure_x4Ga_1-x4As_y4P_1-y4As a first absorption layer, wherein 0<x4<1,0<y4<1 and y4 ═ 2.2 × (1-x4), the first absorbent layer covering part of the lower contact layer;

InP of a second conductivity type is formed as a common contact layer over the first absorption layer;

intrinsic In is formed on the common contact layer_x5Ga_1-x5As_y5P_1-y5Or In_x6Ga_1-x6As As the second absorption layer, wherein 0<x5<1,0<y5<1, y5 ═ 2.2 × (1-x5) and x4<x5；0.53<x6<0.6; the second absorption layer covers part of the common contact layer and is lattice-matched with the InP;

InP of a first conductivity type is formed as an upper contact layer over the second absorption layer;

electrodes are formed on the lower contact layer, the exposed portion of the common contact layer, and the upper contact layer.

4. The hybrid integrated-type two-spectral-segment multispectral short-wave ir detector of claim 3, wherein a corrosion barrier is formed between the InP substrate and the lower contact layer, and the corrosion barrier is completely removed after the InP substrate is completely stripped.

5. The hybrid integrated bispectral shortwave infrared detector of claim 4 wherein the corrosion barrier is In_0.53Ga_0.47As。

6. The hybrid integrated-type dual-spectral-band multispectral short-wave infrared detector of claim 3, wherein in the first structure, the first conductivity type is N-type, the second conductivity type is P-type, and the conductivity type of the lattice-adapted buffer layer is P-type.

7. The hybrid integrated dual-spectral multispectral short-wave infrared detector of claim 6, wherein the lattice-adapted buffer layer is Be-doped.

8. The hybrid integrated type dual-spectral multispectral short-wave infrared detector as claimed in claim 3, wherein in the first structure, the lattice-adapted buffer layer is a multilayer structure, InAlAs or InAsP material with linearly-graded or graded composition is adopted, and through composition modulation, the bottom layer is lattice-matched with the common contact layer, and the upper layer is lattice-matched with the second absorption layer.

9. The hybrid integrated dual-spectral multispectral short-wave ir detector of claim 3, wherein the first structure is a second absorbing layer In_x2Ga_1-x2As has an In component of 0.53 < x2 < 0.83 and a maximum band gap absorption cutoff wavelength of 2.6 μm.

10. The hybrid integrated multispectral short-wave infrared detector of claim 3, wherein in the second structure, the structure of the common contact layer is replaced by the following structure:

an InP first electron barrier layer of a second conductivity type formed over the first absorption layer, and In formed over the first electron barrier layer_x7Ga_1-x7As_y7P_1-y7A filter layer of which 0<x7<1,0<y7<1 and y7 ═ 2.2 × (1-x 7); x4<x7<x 5; and an InP second electronic barrier layer of a second conduction type is formed on the filter layer, the second electronic barrier layer covers part of the filter layer, and electrodes are formed on the lower contact layer, the exposed part of the filter layer and the upper contact layer.

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