WO2013119868A1

WO2013119868A1 - LIGHT TRANSMITTIVE AlN LAYERS AND ASSOCIATED DEVICES AND METHODS

Info

Publication number: WO2013119868A1
Application number: PCT/US2013/025220
Authority: WO
Inventors: Chien-Min Sung
Original assignee: Ritedia Corporation
Priority date: 2012-02-07
Filing date: 2013-02-07
Publication date: 2013-08-15

Abstract

Devices having light transmittant AlN layers and methods associated with such layers are provided. In one aspect, for example, an optoelectronic device can include a semiconductor material having a light interactive surface and a light transmittant AlN 5 layer including at least 50 wt% AlN and having a transmittance of greater than or equal to 80% for light having at least one wavelength from about 250 nm to about 800 nm. Such a device can be utilized with a variety of optoelectronic devices such as, without limitation, LEDs, laser diodes, solar cells, and the like.

Description

LIGHT TRANSMITT1VE AIN LAYERS AND ASSOCIATED DEVICES AND

METHODS

BACKGROUND OF THE INVENTION

Various surfaces that transmit light exhibit degraded efficiencies throughout the lifetime of the device to which they are associated. For example, DVDs, CDs, touch screen, glasses, and the like become scratched through normal use and thus, in some cases, will exhibit degraded performance and even complete failure due to such wear and tear. Numerous materials have been utilized in an attempt to provide protective layers for such devices. In many cases, such materials reduce the transmittance of light through the surface and thus have limited uses. In other cases, the protective material is softer than the underlying surface to be protected, and thus merely transfer any scratching problem to a different material layer. SUMMARY OF THE INVENTION

The present disclosure provides devices having light transmittant AIN layers and methods associated with such layers. In one aspect, for example, an optoelectronic device can include a semiconductor material having a light interactive surface and a light transmittant AIN layer including at least 50 wt% AIN and having a transmittance of greater than or equal to 80% for light having at least one wavelength from about 250 nm to about 800 ran. Such a device can be utilized with a variety of optoelectronic devices such as, without limitation, LEDs, laser diodes, solar cells, and the like. In some aspects the light wavel ength is within the spectrum of light visible to humans.

In another aspect, a SAW-type touch screen device is provided. Such a device can include a support substrate, a piezoelectric AIN layer disposed on the support substrate, at least one SAW emitter functionally coupled to the AIN layer, at least one SAW receiver functionally coupled to the AIN layer and positioned to receive a SAW from the at least one SAW emitter, and a computational circuit electrically coupled to the at least one SAW receiver, the computation circuit being operable to analyze the SAW to determine a disturbance at the AIN layer surface,

There has thus been outlined, rather broadly, the more important features of the invention so that the detailed description thereof that follows may be better understood, and so that the present contribution to the ait may be better appreciated. Other features of the present invention will become clearer from the following detailed description of the invention, taken with the accompanying drawings and claims, or may be learned by the practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-sectional side view of an optical media device in accordance with one embodiment of the present invention,

FIG. 2 shows a cross-sectional side view of an optical media device in accordance with another embodiment of the present invention.

FIG. 3 shows a cross-sectional side view of a touch screen in accordance with yet another embodiment of the present invention.

FIG. 4 shows a top view of a touch screen in accordance with another embodiment of the present invention.

FIG. 5 shows a cross-sectional side view of an optoelectronic device in accordance with yet another embodiment of the present invention.

FIG. 6 shows a cross-sectional side view of an optoelectronic device in accordance with yet another embodiment of the present in vention.

The drawings will be described further in connection with the following detailed description. Further, these drawings are not necessarily to scale and are by way of illustration only such tha t dimensions and geometries can vary from those illustrated.

DETAILED DESCRIPTION

Before the present invention is disclosed and described, it is to be understood that this invention is not limited to the particular structures, process steps, or materials disclosed herein, but is extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.

It must be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "the layer" includes one or more of such layers, reference to "an additive" includes reference to one or more of such materials, and reference to "a cathodic arc technique" includes reference to one or more of such techniques.

Definitions

In describing and claiming the present invention, the following terminology will be used in accordance with the definitions set forth below.

As used herein, "vapor deposited" refers to materials whic are formed using vapor deposition techniques. "Vapor deposition" refers to a process of depositing materials on a substrate through the vapor phase. Vapor deposition processes can include any process such as, but not limited to, chemical vapor deposition (CVD) and physical vapor deposition (PVD). A wide variety of variations of each vapor deposition method can be performed by those skilled in the art . Examples of vapor deposition methods include hot filament CVD, rf-CVD, laser CVD (LCVD), laser ablation, conformal diamond coating processes, metal-organic CVD (MOCVD), sputtering, thermal evaporation PVD, ionized metal PVD (IMPVD), electron beam PVD (EBPVD), reactive PVD, atomic layer deposition (ALD), and the like.

As used herein, the term "light interactive surface" refers to a surface through which light is transmitted. Such transmission can include receiving light and emitting light.

As used herein, the term "substantially" refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking the nearness of completion will be so as to have the same o verall result as if absolute and total completion were obtained. The use of "substantially" is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result. For example, a composition that is "substantially free of particles would either completely lack particles, or so nearly completely lack particles that the effect would be the same as if it completely lacked particles. n other words, a composition that is "substantially free of an ingredient or element may still actually contain such item as long as there is no measurable effect on the property of interest thereof.

As used herein, the term "about" is used to provide flexibility to a numerical range endpoint by providing that a given value may be "a little above" or "a little below" the endpoint with a degree of flexibility as would be generally recognized by those skilled in the art. Further, the term about explicitly includes the exact endpoint, unless specifically stated otherwise.

As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience.

However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary.

Concentrations, amounts, and other numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. As an illustration, a numerical range of "about 1 to about 5" should be interpreted to include not only the explicitly recited values of about 1 to about 5, but also include individual values and sub-ranges within the indicated range, Thus, included in this numerical range are individual values such as 2, 3, and 4 and sub-ranges such as from 1 -3, from 2-4, and from 3-5, etc., as well as 1 , 2, 3, 4, and 5, individually. This same principle applies to ranges reciting only one numerical value as a minimum or a maximum. Furthermore, such an interpretation should apply regardless of the breadth of the range or the characteristics being described.

The Invention

The present disclosure provides light transmitta t protective layers, including devices incorporating such layers, and associated methods. Various surfaces that transmit light exhibit degraded efficiencies throughout the lifetime of the de vice to which they are associated. Such degraded efficiencies can be a result of many factors, non-limiting examples including scratching, accumulation of dirt, oil and other light-blocking or refractive substances, and the like. Additionally, certain electronic devices that transmit light can also be degraded due to thermal effects. The present light traiismittant protective layers can pro vide protection to such surfaces, either by coating there over or replacing the surface altogether. Non-limiting examples of devices that can benefit from such light transmittant protective layers include LEDs, touch screens, optical storage media, S AW filters, and the like.

It has now been discovered that a light transmittant protective layer can be made from AIN materials. Red light photons carry about 1.8 eV of energy, while blue light photons cany about 3.5 eV. AIN has a bandgap of about 6 eV, which is greater than the energy carried by light in the red to blue range. A1N materials are transparent, therefore, to light within this range. This light transparency allows A1N to be used as a protective coating over other light transmittant substrates, such as optical storage media, touch screens, eyeglasses, watch crystals, and the like. In some aspects, an A1N layer can be utilized as the light transmittant substrate rather than as merely a protective light transmittant layer that is applied over the substrate. For example, in one aspect an A1N layer can be used as a thin protective layer that is applied over a touch screen interface, and in another aspect an A1N layer can be used as the touch screen interface itself.

A1N materials can be abrasion resistant and chemically inert, and thus can be used to protect a device against abrasion, scratching, and chemical breakdown. In addition, doping can vary the physical properties of the A1N materials in order to improve various properties for some applications. For example, A1N can be doped with B to increase the hardness and in some cases the transparency of the AIN layer. This can be useful for devices that are easily scratched or otherwise abraded, for device that exhibit decreased performance due to wear over time, or for situations where improved AIN layer hardness is desired. In another aspect, AIN can be doped with Ga, In, or the like in order to improve the electrical conductivity of the AIN material. Electrically conductive AIN layers can be used beneficially in a variety of applications. One example of such an application is as a protective layer for a touch screen. In one aspect of the present disclosure, a device having a light transmittant protective layer is provided. Such a device can include a substrate having a transmittance of greater than or equal to about 85% for light having at least one wavelength from about 250 nm to about 800 nm, and a light transmittant protective layer coated on the substrate. The protective layer includes at least 50 wt% AlN and has a transmittance of greater than or equal to 80% for light ha ving at least one wavelength from about 250 nm to about 800 nm. In another aspect, the protective layer includes at least 75 wt% AlN. Furthermore, in another aspect the protective layer has a transmittance of greater than or equal to 80% for light having at least one wavelength from about 400 nm to about 500 nm. Additionally, in some cases the protective layer can have a thickness that is from about 10 nm to about 1 μηι. In another aspect, the protective layer can have a thickness that is from about 50 nm to about 1 μπι.

In one aspect of the present disclosure, a light transmittant protective layer can be applied to an optical storage media device. For example, FIG. 1 shows a light transmittant substrate 12 having an associated recording layer 14. A light transmittant protective layer 16 is applied to the substrate 12. In this case, light 18 from a reading device such as a laser impinges on the recording layer 14 after passing through the protective layer 16 and the substrate 12. The protective layer 16 can thus provide added protection to the substrate to increase the longevity of the optical storage media as well as reducing scratches and abrasions. The protective layer can include AlN, and in some cases the AlN can be B doped in order to increase the hardness and durability of the layer. The materials used in the substrates of optical storage media can vary, but are generally a polymeric substance such as polycarbonate. By coating the substrate with AlN, the added hardness wil l increase the scratch resistance of the optical storage media device. Additionally, the light transmittant properties of AlN allow the unimpeded access of the laser light through the substrate and onto the recordmg layer. This is particularly beneficial for optical storage media readers that utilize blue laser light, such as Biu-Ray disks, as AlN is particularly transparent to blue light wavelengths as compared to many other coating materials.

The structure of an optical storage media device can vary depending on the type of device and the system used for reading. As is shown in FIG. 2, for example, a light transmittant substrate 12 having an associated recording layer 14 and a light transmittant protective layer 16 is shown. As was shown in FIG. 1 , light 18 from the reading device impinges on the recording layer 14 after passing through the protective layer 16 and the substrate 12. A support substrate 20 is coupled to the recording layer 14 opposite the light transmittant substrate 12. This structural configuration is similar to DVD and Blu-Ray disks.

Any type of optical storage media known can benefit from the AIN protective layers of the present disclosure. Non-limiting examples of such media include CDs, DVDs, Blu-Ray disks, rewritable optical storage media, and the like. In one aspect, the optical storage media device can be a DVD and/or a Blu-Ray disk. In another aspect, the optical storage media device is capable of storing greater than 10 GB of data on a single disk. Regardless of the type of device, optical storage media can be protected through the applica tion of a pro tective AIN layer over the surface through which the laser or optical reading source passes. Additionally, in some aspects the AIN layer can be applied directly to the recording layer, and thus replace the light transmittant substrate of many current optical storage media designs. This may be particularly beneficial for optical storage media such as Blu-Ray, where the light transmittant substrate is already very thin relative to the overall thickness of the disk.

in another aspect, light transmittant protective layers can be utilized to provide additional protection to touch screen devices. Various designs for touch screen devices are contemplated, and any such design is considered to be within the present scope. Non-limiting examples of touch screen technologies include resistive, capacitive, surface acoustic wave (SAW), infrared, optical imaging, acoustic pulse recognition, dispersive signal technology, and the like. Thus, regardless of the technology, a touch screen can be coated with a light transmittant protective layer to provided added protection to the device. Because the AIN material is transmittant to visible light, images displayed by the touch screen are readily transmitted through the AIN material and viewed by a user. As is shown in FIG. 3, for example, a light transmittant protective layer 32 that includes AIN material is disposed onto a touch screen 34. If the touch screen technology utilizes an electrical property change to sense screen touches, the AIN layer can be doped with a dopant such as Ga or In to increase the conductivity of the layer, thus allowing finger touches to be registered through the AIN layer, For example, one touch screen design based on capacitance change utilizes a grid of indium tin oxide (ΠΌ) electrodes running in perpendicular directions. The perpendicular ΓΓΟ electrodes are insulated from one another, and therefore can detect the capacitance changes of a finger touch. A conductive AIN layer can thus be applied to such a touch screen to provide protection to the device. The AIN layer can additionally be doped with B to increase the hardness of the layer, thereby increasing the durability of the device.

In another aspect, the AIN layer can be utilized in conjunction with a SAW-type touch screen. AIN materials exhibit a piezoelectric effect due, at least in part, to a hexagonal wurtzite crystal structure. The high shear modulus and low density of this material can support very high surface acoustic wave (SAW) frequencies. SAW touch screens can include acoustic waves generated across the surface of the touch region of the screen. This can be accomplished via SAW emitters and receivers embedded around the periphery of the touch screen that generate acoustic waves through the AIN layer, Any disturbance of the acoustic wa ve that impinges on the screen is thus detected by the scattering of the acoustic waves over that surface. Thus, the wave pattern is analyzed and the location of the touch is determined relative to the edges of the screen. One example aspect of such a device is show in FIG. 4. An AI N layer 42 is functionally coupled to at least one SAW emitter 44 and at least one SAW receiver 46. The AIN layer can be deposited directly onto a touch screen substrate such as glass, thus eliminating much of the complexity and cost of traditional conductive-type screens. The number and positioning of the SAW emitter(s) and SAW receivers) can vary depending on the design of the device, and should not be seen as limiting. The output from the S AW receivers can be sent to a computational system (not shown) such as an integrated circuit that is capable of determining the locations of any disturbances of the acoustic wave relative to the surface of the touch screen. Thus a pattern of single or multiple touches of an object such as a finger can be detected and the locations of such touches can be determined. Additionally, the AIN can be doped with a dopant such as B to further increase the hardness of the AIN layer, thus increasing the speed of the acoustic wave.

In addition to disturbances of the surface acoustic wave by physical objects, in one aspect the S AW touch screen can be configured to detect externally generated acoustic waves. For example, the AIN layer can be configured to detect an incident acoustic signal, such as for example, speech sounds. In this case, a user can speak toward the AIN layer, and such an acoustic signal can cause distortions in the S AW signal such that the speech can be detected. The AIN layer can thus function as a microphone for the touch screen device. The detection of externally generated acoustic waves can be accomplished using the same SAW system used to detect physical touch, or it can be detected using a separate SAW system operating at different SAW frequencies and/or sensitivities.

Depending on the design of the touch screen, in some cases an externally generated acoustic wave may not have sufficient amplitude to be detected by the peripheral SA W detectors. As such, in one aspect a disturbance in the SAW field can produce an electrical signal locally near the disturbance point and transmitted to the periphery of the touch screen to be analyzed. In one exemplary aspect, a series of parallel conductors can be deposited at the interface between the AIN and the underlying substrate (i.e. glass), Although any electrically conductive conductor is contemplated, in one exemplary aspect Al ca be sputtered or evaporated at the interface. In a further aspect, an additional piezoelectric layer, such as PZT, can be coated on the underlying substrate either above or below the parallel conductors. A piezoelectric layer such as PZT has a higher coupling coefficient than AIN and may increase the detection of weaker signals. The parallel conductors can also be arranged as a grid, provided the two parallel sets of conductors are electrically insulated from one another. In one aspect, an additional layer of AIN or other piezoelectric material can be applied therebetween to provide this electrical insulation. It should be noted that the idea of parallel conductors ca be utilized in aspects whereby touch is being detected such that the generation of local electrical signals functions to increase the sensitivity of the device.

In yet another aspect, the SAW AIN layer can be configured to function as an acoustic emitter. As such, the AIN layer can be vibrated at sufficient amplitudes and frequencies to created acoustic signals in the air, thus functioning similar to a speaker.

As noted above, various dopants can enhance or control the hardness and/or the conductivity of the AIN layer. Any dopant that can be used to improve the AIN layer is considered to be within the present scope, including for example, B, Ga, In, conductive metals, and the like, including combinations thereof. In one specific aspect, the A!N layer is doped with a B dopant. The amount of B dopant in the AIN layer is contemplated to be that which is sufficient to pro vide the desired properties of the layer. In one aspect, for however, the B dopant is doped into the AI layer at a concentration of from about 5 at% to about 15 at%. In another aspect, the B dopant is doped into the AIN layer at a concentration of from about 10 at% to about 15 at%. As a non- limi ing example of B doping of AIN, an A1N:B target can be sputtered onto a substra te to form the protective AIN layer having increased hardness,

Additionally, it can be beneficial to inhibit water and/or oils from collecting on the surface of the A!N layer. In some aspects, the AIN layer can be doped with a dopant that can reduce the adherence of oils, such as for example, F or H doping. In another aspect, a material such as diamond-like carbon (DLC) can be applied to the AIN material to inhibit the ac tual touching of the AIN layer. Such a material can thus inhibit water and oil from collecting on the AIN surface. The DLC material can be applied as a pattern of micron or nano-sized dots, or as any other pattern, such as for example, a lined grid. In such cases, a methane-coated DLC material can be utilized to repel water from the layer surface. DLC can also be applied as a layer to the AIN layer. DLC normally poorly adheres to glass. AIN coated on Si0₂ glass can form SiASON, a ceramic that has a good range of chemical compatibilities. This ceramic layer can thus promote the adherence of DLC to glass.

In another aspect, the AIN layer is doped with a Ga dopant. The amount of Ga dopant in the AIN layer is contemplated to be that which is sufficient to provide the desired properties of the layer. In one aspect, however, the Ga dopant is doped into the AIN layer at a concentration of from about 5 at% to about 90 at%, In another aspect the Ga dopant is doped into the AIN layer at a concentration of from about 25 at% to about 90 at%. In another aspect the Ga dopant is doped into the AIN layer at a concentration of from about 5 at% to about 50 at%. Doping can occur during or following the formation of the AIN layer. Such doping techniques would be readily understood by one of ordinary skill in the art once in possession of the present disclosure.

Furthermore, the degree of electrical conductivity of the AIN layer can vary depending on the desired properties and uses of the layer, and any degree of electrical conductivity is considered to be within the present scope. In one aspect, however, the AIN layer has an electrical resistivity of from about l .Oxl.0^"4 to about 3.0 l0^"4 ohm cm. In another aspect, the ASN layer has an electrical resisti vity of from about 1.0 10^"* to about 2.5x10^~4 ohm cm. In yet another aspect, the AIN layer has an electrical resistivity of from about l .O lO^"4 to about 2.0 10^"4 ohm cm. Furthermore, in some aspects similar results can be achieved by doping with other dopants such as In. As a non-limiting example of Ga doping of AIN, an AlN:Ga target can be made by forming an alloy of AlGa and sputtering in a nitrogen atmosphere.

One issue that can arise with the sputtering of A1N from an AIN target is the overabundance of Al atoms in the target. A high excess A! concentration in the AIN layer can inhibit light transmittance and increase the hydrophiSicity of the A SN lay er. Free Al can be reduced or eliminated in the forming layer by sputtering in an atmosphere containing N. In this way, N will be incorporated into the layer with Al, thus forming AIN. A greater N atomic % can also be incorporated into the target to reduce the free Al in the resulting AIN layer.

Numerous substrates upon which the AIN layer is deposited are contemplated, and these substrates include light transmittant substrates and non-light transmittant substrates, in those aspects where the AIN layer is applied to a light transmittant substrate, any substrate material capable of transmitting Sight and receiving a protective AI layer deposited thereon would be considered to be within the present scope. Non-limiting examples include glass materials, polymeric materials, semiconductor materials, diamond materials, and the like, including combinations thereof. In one aspect, the light transmitting substrate can be a polymeric material. In one specific aspect, the polymeric material can be a polycarbonate. In one aspect, the AIN layer can be deposited onto a diamond substrate such as, for example, polycrystalline diamond. In those aspects where the AIN layer is deposited onto a substrate as a replacement for a light transmittant substrate, any substrate material capable of receiving a protecti ve AIN layer deposited thereon is considered to be within the present scope. Non-limiting examples include metal materials, ceramic materials, semiconductor materials, polymeric materials, and the like, including combinations thereof.

The protective and light transmittant AIN layers of the present disclosure can be deposited on a substrate by any technique capable of depositing AIN material in a manner that results in a layer having light transmittant properties. In one aspect, for example, the AIN material can be deposited by a vapor deposition process. Such vapor deposition processes can include chemical vapor deposition (CVD) and physical vapor deposition (PVD) techniques. In one specific example, the AIN protective layer can he deposited by a PVD process. Non-limiting examples of suitable processes include vapor deposition, cathodic arc deposition, ion bombardment, RF coupling, electron beam PVD, evaporative deposition, pulsed laser deposition, sputtering, magnetron sputtering, and the like. In one specific aspect, the PVD deposition can be by sputtering. Sputtering is capable of depositing AIN layers onto a variety of substrate materials at a lower cost than CVD deposition techniques, in one specific aspect, AIN can be deposited by MOCVD.

Additionally, in another aspect, an AIN layer can be formed by depositing AIN material on a substrate and hardening the layer into a protective AIN layer. For example, in one aspect and AIN material can be deposited onto a substrate to form a protective layer precursor by a process such as screen printing, ink-jet printing, spraying, and the like. The protective layer precursor can then be heated to form a protective layer of the AIN material,

The A IN layer can be deposited onto an entire surface of a substrate or only a portion thereof, depending on the desired configuration of the protecti ve layer.

Additionally, AIN layers can have various thicknesses. In some aspects, only very thin layers may be adequate to achieve a desired result, where other aspects utilize relatively thick layers, As such, the present scope is not limited by AIN layer thickness. Tha being said, in one aspect the AIN layer can have a thickness of from about 100 μηι to about 1 mm. In another aspect, the AIN layer can have a thickness of from about 10 μιη to about 100 μιη. In yet another aspect, the AIN layer can ha ve a thickness of from about 100 nm to about 10 μηι. In a further aspect, the AI layer can have a thickness of from about 10 nm to about 1 μτη, in yet a further aspect, the AIN layer can have a thickness of from about 10 nm to about 30 nm. In some aspects, the AIN layer can have a thickness of from about 1 nm to about 100 nm. It should be noted that, in some cases, the transmittance of PVD AIN layers is facilitated for thicknesses of less than about 100 nm.

The present disclosure additionally provides methods of protective a light transmitting substrate of a device. In one aspect, one such method ca include depositing a light transmittant protective layer on a light transmitting substrate, where the protective layer includes at least 50 wt% AIN and has a transmittance of greater than or equal to 80% for light having at least one wavelength from about 250 nm to about 800 nm. Additionally, the substrate has a transmittance of greater than or equal to 85% for light having at least one wavelength from about 250 nm to about 800 nm.

In ano ther aspect of the present disclosure, an AIN coating can be incorporated into various optoelectronic devices such as solar cells, LEDs, laser diodes, and the like. The AIN layer ca be coated over a light interacting surface to provide protection to the optoelectronic device. In some aspects, the AIN layer can be utilized as a protective layer, while in other aspects the AI N layer can be used as a part of a junction, such as a p-n, p-i-n, or the like. In one specific aspect, AIN can be doped with a dopant to form an n-type semiconductor material. Any dopant capable of producing such a semiconductive material is considered to be within the present scope. Non-limiting examples can include Si or an excess of Al. In cases where excess Al is utilized, deposition in a nitrogen environment can nitridize the Al to maintain the transparent nature of the material. A variety of materials an d/or dopan ts can be utilized to form a p-type semiconductive material associated with the AIN layer. Any such material or dopant is considered to be within the present scope. In one aspect, for example, the material can be SiC and the dopant can be B. As is shown in FIG. 5, for example, an optoelectronic device 52 can include an AIN layer 54 coated on at least one surface. The AIN layer can be coated on the light interactive surface. For aspects whereby the AIN layer 54 forms a portion of a semiconductive junction, the optoelectronic device 52 can include a semiconductive layer adjacent to the AIN layer that is at least partially doped.

In another aspect of the present disclosure, an AIN layer can be utilized as an optical mterlayer to increase the efficiency of an optoelectronic device such as an LED. Thus the AIN layer can reduce refraction of light emitted from the LED, thus increasing output and efficiency. In the case of a GaN LED, for example, GaN has a high refractive index resulting in reflected light. An AIN material with a refractive index of about 2 is intermediate between GaN and air, which will help direct light forward and out of the LED. As such, the intensity of the emitted light will be increased. In another aspect, an AIN can be used as an optical interlayer between the LED and a lens, such as a phosphor-containing silicone lens. In one example, as is shown in FIG. 6, an LED 62 having a GaN light emitting layer 64, is coated with an A1N layer 66. A silicon lens 68 containing phosphor is deposited onto the AIN layer 66. The refractive index of AIN is intermediate between the GaN and the silicon, thus reducing the refraction of light between the GaN layer 64 and the silicon lens 68 and increasing the light extraction of the LED device. Furthermore, AIN has a high thermal conductivity (about 150 W/mK) that can facilitate die spreading of heat from the phosphor in the silicon lens. As another benefit, the AIN layer can passivate the GaN surface, thus reducing current leakage.

The following are examples illustrate various methods of making electronic devices in accordance with the present invention. However, it is to be understood that the following are only exemplary or illustrative of the application of the principles of the present invention. Numerous modifications and alternative compositions, methods, and systems can be devised by those skilled in the art without departing from the spirit and scope of the present invention. The appended claims are intended to cover such modifications and arrangements. Thus, while the present invention has been described above with particularity, the following Examples provide farther detail in connection with several specific embodiments of the invention.

Examples

Example 1

A glass panel is coated with an AIN layer and doped such that 10% of Al atoms are replaced with B atoms. The four edges of the AIN layer are coated (e.g. sputter or vapor deposition) with dots of Al that are connected to electrodes. Two are connected to emitters and the other two to receivers. Opposite edges are dotted with emitters on one side and receivers on the other. When a voltage is applied to the emitter, a surface acoustic wave (SAW) is generated that moves to the opposite side of AIN layer where the receivers reside. If a touch point is not present, the waves will move in parallel. But if a touch point is present, the SAWs are scattered. The receivers can thus detect the perturbations of the SAWs at various locations along the AIN layer periphery. These perturbations can be interpreted by an IC processor to determine the locations and sizes of the touched points, the pressure distribution of each touch , and mo vements of individual point where touching has occurred.

Example 2

A Mo substrate is sputtered with SiC doped with B, and then A1N doped with

Si, each about 2 microns thick. The thin film is subject to hot pressing to regrow the crystals so that rmcrocrystalline crystals are formed from the amorphous film. The P-N junction can be used for an optoelectronic device such as an LED or a solar cells. Of course, it is to be understood that the above-described arrangements are only illustrative of the application of the principles of the present invention. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of the present invention and the appended claims are intended to cover such modifications and arrangements. Thus, while the present invention has been described above with particularity and detail in connection with what is presently deemed to be the most practical and preferred embodiments of the in vention, it will be apparent to those of ordinary_' skill in the art that numerous modifications, including, but not limited to, variations in size, materials, shape, form, function and manner of operation, assembly and use may be made without departing from the principles and concepts set forth herein.

Claims

CLAIMS What is claimed is:

1. An optoelectronic device, comprising:

a semiconductor material having a light interactive surface; and

a light transmittant AIN layer including at least 50 wt% AIN and having a transmittance of greater than or equal to 80% for light having at least one wa velength from about 250 nm to about 800 ran.

2. The device of claim 1 , wherein the protective layer includes at least 75 wt% AIN.

3. The device of claim 1 , wherein the protective layer has a transmittance of greater than or equal to 80% for light having at least one wavelength from about 400 nm to about 500 nm,

4. The device of claim 1, wherein the device includes a member selected from the group consisting of LEDs, laser diodes, solar cells, and combinations thereof.

5. The device of claim 1, wherein the semiconductor material is GaN.

6. The device of claim 1, further comprising a silicon lens coupled to the AIN layer, such that the AIN layer is positioned between the lens and the GaN layer.

7. The de vice of claim 6, wherein the AIN l ayer is positioned directly between the lens and the GaN layer.

8. The device of claim 1, wherein at least a portion of the AIN layer is doped with an n-type dopant.

9. The device of claim 8, wherein the n-type dopant is Si,

10. The device of claim 8, wherein at least a portion of the semiconductor material is doped with a p-type dopant.

1 1. The device of claim 8, wherein the semiconductor material is SiC.

12. A SAW-type touch screen device, comprising:

a support substrate;

an AIN layer disposed on the support substrate;

at least one SAW emitter functionally coupled to the AIN layer;

at least one SAW receiver functionally coupled to the AIN layer and positioned to receive a SAW from the at least one SAW emitter; and

a computational circuit electrically coupled to the at least one SAW receiver, the computation circuit being operable to analyze the SAW to determine a disturbance at the AIN layer surface.

13. The device of claim 12, wherein the at least one SAW receiver is multiple SAW receivers positioned to substantially simultaneously detect multiple disturbance points at the AIN layer surface.

14. The device of claim 13, wherein the SAW receivers are operable to detect an external acoustic signal.

15. The device of claim 12, wherein the at least one SAW emitter is multiple SAW emitters positioned and operate as an acoustic speaker.

16. The device of claim 12, further comprising a series of parallel conductors disposed between the support substrate and the AIN layer such that a SAW disturbance at the AIN layer surface is capable of generating an electrical signal in at least one parallel conductor.

17. The device of claim 16, further comprising anon-AIN piezoelectric layer disposed between the AIN layer and the series of parallel conductors.

18. The device of claim 16, further comprising:

a second series of parallel conductors arranged substantially orthogonal to the series of parallel conductors; and

an insulating piezoelectric layer located between the series of parallel conductors and the second series of parallel conductors, wherein the insulating piezoelectric layer is operable to electrically insulate the series of parallel conductors from the second series of parallel conductors.