CN101295636A - Production method of pattern underlay for epitaxial growth of high-crystal quality nitride - Google Patents
Production method of pattern underlay for epitaxial growth of high-crystal quality nitride Download PDFInfo
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- CN101295636A CN101295636A CNA2007100987028A CN200710098702A CN101295636A CN 101295636 A CN101295636 A CN 101295636A CN A2007100987028 A CNA2007100987028 A CN A2007100987028A CN 200710098702 A CN200710098702 A CN 200710098702A CN 101295636 A CN101295636 A CN 101295636A
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Abstract
The invention relates to a preparation method for a graph underlay used for the epitaxial growth of a nitride with high crystal quality, which is characterized by including the steps of: step 1: depositing a layer of thin metal layer on the underlay; step 2: carrying out annealing treatment to lead the thin metal layer to form the amorphous graph of a metal mask with a micron dimension by self organizing; step 3: carrying out dry etching to transfer the graph of the metal mask to the underlay; step 4: removing the residual metal mask by adopting a method for wet corrosion and washing the underlay to prepare and finish the graph underlay.
Description
Technical field
The invention belongs to technical field of semiconductors, be meant the preparation method of the used graph substrate of a kind of epitaxial growth of high-crystal quality nitride especially.This graph substrate can be used for the epitaxial growth of low-dislocation-density, high-crystal quality nitride.
Background technology
The broad stopband nitride compound semiconductor (as GaN, InN, AlN, AlGaN, InGaN, AlInN or AlInGaN etc.) that with III-V family gallium nitride (GaN) is representative has important and uses widely in all many-sides such as UV/blue/green light LED, laser, sunlight blind UV electric explorer and high frequency, high temperature high power electronic devices.The main heteroepitaxial growth of nitride on sapphire, silicon, carborundum, zinc oxide, the gallium arsenide substrate or isoepitaxial growth on the self-standing gan substrate.Except that the self-standing gan substrate, there are very macrolattice constant mismatch and thermal expansion coefficient difference between other substrates and nitride, therefore utilize in the nitride epitaxial layer of metal organic chemical vapor deposition (MOCVD), hydride gas-phase epitaxy (HVPE) or molecular beam epitaxy (MBE) homepitaxy technology growth and have very big stress and a lot of crystal defects such as dislocation etc., therefore the crystal mass of material is subjected to very big influence, so deterioration device performance.And adopt the patterned substrate technology can alleviate the stress that causes owing to lattice mismatch in substrate and the nitride epitaxial layer heteroepitaxial growth, and make it to obtain effective relaxation, avoid the generation of crackle.Simultaneously, also can reduce the dislocation density in the epitaxially grown nitride material greatly, crystal mass is greatly improved.The patterned substrate of preparation is to adopt traditional photoetching process preparation mostly at present, is about to litho pattern and transfers to silicon dioxide (SiO
2) or silicon nitride (SiN
4) on the layer, utilize reactive ion (RIE) or inductive couple plasma equipment dry etchings such as (ICP) to form again.Because this complex technical process, cost are higher, and figure limits by lithography layout, so development cost patterned substrate technology low, that be easy to realize just seems more and more important.
Summary of the invention
The objective of the invention is to be to provide the preparation method of the used graph substrate of a kind of epitaxial growth of high-crystal quality nitride, this method can reduce the dislocation density in the nitride epitaxial layer effectively, improve the crystal mass of epitaxial material, and then can improve the performance of photoelectric device; This technology of preparing does not need photoetching, has that making step is few, technology is simple, low cost and other advantages.
The preparation method of the used graph substrate of a kind of epitaxial growth of high-crystal quality nitride of the present invention is characterized in that, comprises the steps:
Step 1: deposit layer of metal thin layer on substrate;
Step 2: carry out annealing in process, make the thin metal layer self-organizing form the figure of the metal mask of unbodied, micro-meter scale;
Step 3: carry out dry etching, with the figure transfer of metal mask to substrate;
Step 4: adopt the method for wet etching, remove remaining metal mask, and substrate is cleaned up, graph substrate is finished in preparation.
Wherein said substrate is the patterned substrate that is used for nitride epitaxial growth.
The patterned substrate of wherein said nitride epitaxial growth is any in sapphire, silicon, carborundum, GaAs, zinc oxide, the self-standing gan.
Wherein thin metal layer is any among Ni, Ti, Au or the Al.
Wherein the thickness of metals deposited thin layer is that 5nm is to 30nm.
The wherein said annealing in process of carrying out, its annealing conditions is at N
2Under the atmosphere that flows, temperature is at 500 ℃ to 1100 ℃, and annealing time is 30 seconds to 30 minutes.
Description of drawings
In order to further specify technology contents of the present invention, below in conjunction with the example of implementing the present invention is done a detailed description, wherein:
Fig. 1 is the substrate deposit layer of metal thin layer figure that is used for nitride epitaxial growth;
Fig. 2 be used for the substrate depositing metal thin layer of nitride epitaxial growth annealed after, form the structural profile schematic diagram behind the figure mask;
Fig. 3 utilizes patterned metal to be mask, adopts ICP or RIE method etched substrate, with the generalized section of figure transfer behind the substrate;
Fig. 4 is after wet etching removes remaining metal, and substrate is cleaned up, and is prepared into the generalized section after the graph substrate;
Fig. 5 is the surface topography photo of the patterned substrate of scanning electron microscopy (SEM) observation;
Fig. 6 is the surface topography photo of the patterned substrate of atomic force microscope (AFM) observation.
Specific embodiment
See also Fig. 1 to Fig. 4, the present invention is the preparation method of the used graph substrate of a kind of epitaxial growth of high-crystal quality nitride, comprises the steps:
Step 1: deposit layer of metal thin layer 2 (as Fig. 1) on substrate 1; Described substrate 1 is for being used for the patterned substrate of nitride epitaxial growth; The patterned substrate of described nitride epitaxial growth is any in sapphire, silicon, carborundum, GaAs, zinc oxide, the self-standing gan; The patterned substrate of described nitride epitaxial growth is c face (0001), m face (1010), any in r face (1102) or a face (1120); The effect of described substrate 1 is in order to etch figure, and growing high-quality nitride thereon; Described thin metal layer 2 is any among Ni, Ti, Au or the Al; The thickness of described thin metal layer 2 is that 5nm is to 30nm; The effect of described thin metal layer 2 is in order to make mask layer after annealing.
Step 2: carry out annealing in process (as Fig. 2), make thin metal layer 2 self-organizings form the figure of the metal mask of unbodied, micro-meter scale; The described annealing in process of carrying out, its annealing conditions are that temperature is at 500 ℃ to 1100 ℃ under N2 flows atmosphere, and annealing time is 30 seconds to 30 minutes; Described annealing process is that the thin metal layer 2 of will grow on substrate 1 is heated to crystallization temperature in closed container, make metal reach crystallization temperature, process change by crystallization again is the pattern of the thin metal layer 2 of tiling on substrate 1 originally, become the figure of the metal mask of unbodied micro-meter scale, the effect of described annealing process is to allow metal crystallization again, makes pattern reach the effect that can realize metal mask.
Step 3: carry out dry etching (as Fig. 3), with the figure transfer of metal mask to substrate 1; Described dry etching comprises and utilizes reactive ion (RIE) or inductive couple plasma equipment such as (ICP) to carry out dry etching, utilizes high energy beam substrate to be removed the processing of material; Described metal mask, be meant that formed metallic pattern is deposited on the substrate when step 2, the part that is hidden by metal on the substrate when dry etching is kept, and the part that is hidden by metal level is not etched away, and the figure transfer of the back metal of will annealing like this is to substrate.
Step 4: adopt the method (as Fig. 4) of wet etching, remove remaining thin metal layer, and substrate is cleaned up, graph substrate is finished in preparation; Described wet etching is meant substrate and together puts into solution and to corrode together with metals deposited thereon, removes remaining thin metal layer; Described graph substrate can be alleviated the stress that causes owing to lattice mismatch in substrate and the nitride epitaxial layer heteroepitaxial growth, makes it to obtain effective relaxation, avoids the generation of crackle; Simultaneously, also can reduce the dislocation density in the epitaxially grown nitride material greatly, crystal mass is greatly improved; Described nitride epitaxial layer is any or several layer structural material that are combined in gallium nitride (GaN), aluminium nitride (AlN), indium nitride (InN), aluminium gallium nitride alloy (AlGaN), indium gallium nitride (InGaN), aluminum indium nitride (AlInN) or the aluminum indium gallium nitride (AlGaInN); The equipment of described nitride epitaxial growth be metal organic chemical vapor deposition (MOCVD), hydride gas-phase epitaxy (HVPE) or molecular beam epitaxy (MBE) in any or several combinations.
Further set forth technical characterstic of the present invention and obvious improvement below by a specific embodiment.
Embodiment
Present embodiment is a kind of figure c face of nitride epitaxial growth or manufacture method of (0001) Sapphire Substrate of being used for.The c surface sapphire substrate is one of the most frequently used backing material of present epitaxial growth nitride.
The metallic nickel (Ni) of deposit 15nm on 2 inches c surface sapphire substrate at first, structural profile schematic diagram as shown in Figure 1, then at N
2Air-flow is down moving, anneals for 800 ℃, and annealing time is 5 minutes, and the structural profile schematic diagram as shown in Figure 2;
Then utilize Ni as the figure mask, utilize ICP equipment dry etching substrate 60 seconds, mask pattern is transferred on the Sapphire Substrate, structural profile as shown in Figure 3;
Used hot HNO3 corrosion substrate then 10 minutes, and removed the Ni on the Sapphire Substrate, and clean Sapphire Substrate, promptly can be made into the graphical sapphire substrate, structural profile as shown in Figure 4;
Fig. 5 is the surface topography map of the Sapphire Substrate behind electronic scanner microscope (SEM) the observation etching figure.Its figure has amorphism, yardstick at micrometer range;
Fig. 6 is the surface topography map of the Sapphire Substrate behind atomic force microscope (AFM) the observation etching figure.Its figure table surface height is about 500nm.
It is simple etc. that this preparation method has the photoetching of need not, low cost, technology Advantage. Adopt the graphical sapphire substrate technology can alleviate the sapphire lining Cause owing to lattice mismatch in the heteroepitaxial growth process between the end and nitride Stress, reduce the defect concentration of nitride epitaxial layer, improve crystal matter Amount, and then improve performance of devices.
Claims (6)
1, the preparation method of the used graph substrate of a kind of epitaxial growth of high-crystal quality nitride is characterized in that, comprises the steps:
Step 1: deposit layer of metal thin layer on substrate;
Step 2: carry out annealing in process, make the thin metal layer self-organizing form the figure of the metal mask of unbodied, micro-meter scale;
Step 3: carry out dry etching, with the figure transfer of metal mask to substrate;
Step 4: adopt the method for wet etching, remove remaining metal mask, and substrate is cleaned up, graph substrate is finished in preparation.
2, the preparation method of the used graph substrate of epitaxial growth of high-crystal quality nitride according to claim 1 is characterized in that, wherein said substrate is the patterned substrate that is used for nitride epitaxial growth.
3, the preparation method of the used graph substrate of epitaxial growth of high-crystal quality nitride according to claim 2, it is characterized in that the patterned substrate of wherein said nitride epitaxial growth is any in sapphire, silicon, carborundum, GaAs, zinc oxide, the self-standing gan.
4, the preparation method of the used graph substrate of epitaxial growth of high-crystal quality nitride according to claim 1 is characterized in that, wherein thin metal layer is any among Ni, Ti, Au or the Al.
According to the preparation method of claim 1 or the used graph substrate of 4 described epitaxial growth of high-crystal quality nitride, it is characterized in that 5, wherein the thickness of metals deposited thin layer is that 5nm is to 30nm.
6, the preparation method of the used graph substrate of epitaxial growth of high-crystal quality nitride according to claim 1 is characterized in that, the wherein said annealing in process of carrying out, and its annealing conditions is at N
2Under the atmosphere that flows, temperature is at 500 ℃ to 1100 ℃, and annealing time is 30 seconds to 30 minutes.
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