Photoresponse HEMT device and preparation method thereof
By forming a p-type doped h-BN array on the barrier layer of the HEMT device, a p-hBN/n-AlGaN heterojunction is formed, which solves the problem of the lack of optical response capability of traditional GaN HEMT devices and realizes high photocurrent optical response capability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-15
- Publication Date
- 2026-03-24
AI Technical Summary
Traditional GaN HEMT devices lack optical response capabilities, which limits their application in fields such as optoelectronic communication and optoelectronic sensors.
A P-type doped h-BN array is formed on the barrier layer of the HEMT device to form a p-hBN/n-AlGaN heterojunction. The conductive channel is turned off under dark conditions by utilizing the built-in electric field, and photogenerated electron-hole pairs are separated under ultraviolet light to achieve optical response.
Achieving high photocurrent under ultraviolet light solves the problem of insufficient optical response capability of traditional GaN HEMT devices and enhances the optical response capability of the devices.
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Figure CN121728795A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of semiconductor manufacturing, in particular to a light-responsive HEMT device and a preparation method thereof. BACKGROUND
[0002] Gallium nitride (GaN) is a wide-bandgap semiconductor material with high electron mobility, high saturation electron velocity, high breakdown electric field strength, and high thermal conductivity. These excellent characteristics make it widely used in high-frequency, high-power, and other application scenarios to achieve low-loss and high-efficiency electron transport.
[0003] GaN HEMT devices form a heterojunction structure by growing a layer of aluminum gallium nitride (AlGaN) or aluminum nitride (AlN) on a gallium nitride layer. At the AlGaN / GaN heterojunction interface, a high-concentration, high-mobility two-dimensional electron gas (2DEG) is automatically generated due to spontaneous polarization and piezoelectric polarization effects. These electrons are confined to move in a two-dimensional plane, reducing scattering loss and achieving extremely high electron mobility. Therefore, it is widely used in high-frequency power conversion, radio frequency communication, fast charging, 5G base stations, data center power supplies, vehicle charging, and other fields. Its high-frequency and high-efficiency characteristics can significantly improve system performance, reduce device size, and reduce energy consumption. It is one of the key devices that promote the development of modern electronic technology towards high frequency, high power, and high efficiency.
[0004] However, traditional GaN HEMT devices have limitations in optoelectronic applications, such as lack of optical response capability and lack of optical signal control capability under high power density, which limits the application of GaN HEMT in optoelectronic communication, optoelectronic sensors, and other fields. SUMMARY
[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a light-responsive HEMT device and a preparation method thereof, which solves the problem of lack of optical response capability of HEMT devices in the prior art.
[0006] To achieve the above-mentioned purposes and other related purposes, the present application provides a preparation method of a light-responsive HEMT device, which comprises the following steps:
[0007] S1, providing a stack structure, the stack structure comprising a channel layer, a barrier layer located on the channel layer, and a P-type doped h-BN layer located on the barrier layer;
[0008] S2, performing photoetching patterning on the P-type doped h-BN layer to obtain a P-type doped h-BN array; wherein the P-type doped h-BN array comprises at least one P-type doped h-BN structure;
[0009] S3, forming a source electrode, a drain electrode and a gate electrode on the barrier layer; wherein the source electrode and the drain electrode are separately arranged on two sides of the gate electrode, and all the P-type doped h-BN structures are arranged between the source electrode and the gate electrode and / or between the drain electrode and the gate electrode;
[0010] S4, forming a dielectric layer covering the P-type doped h-BN array and the source electrode, the drain electrode and the gate electrode on the barrier layer;
[0011] S5, forming a pad on the dielectric layer, wherein the pad comprises a pad light via and / or a pad light blind slot, and each of the pad light via and / or the pad light blind slot exposes at least one P-type doped h-BN structure in the vertical direction.
[0012] Optionally, after step S4, the method further comprises a step of forming a field plate in the dielectric layer between the gate electrode and the drain electrode; wherein the field plate comprises a field plate light via and / or a field plate light blind slot, and each of the field plate light via and / or the field plate light blind slot exposes a corresponding P-type doped h-BN structure in the vertical direction.
[0013] The application further provides a light-responsive HEMT device, which comprises:
[0014] a channel layer;
[0015] a barrier layer arranged on the channel layer;
[0016] a source electrode, a drain electrode and a gate electrode arranged on the barrier layer; wherein the source electrode and the drain electrode are separately arranged on two sides of the gate electrode;
[0017] a P-type doped h-BN array comprising at least one P-type doped h-BN structure, and all the P-type doped h-BN structures are arranged on the barrier layer between the source electrode and the gate electrode and / or between the drain electrode and the gate electrode;
[0018] a dielectric layer arranged on the barrier layer and covering the P-type doped h-BN array and the source electrode, the drain electrode and the gate electrode;
[0019] a pad arranged on the dielectric layer, wherein the pad comprises a pad light via and / or a pad light blind slot, and each of the pad light via and / or the pad light blind slot exposes at least one P-type doped h-BN structure in the vertical direction.
[0020] Optionally, the device further comprises a field plate arranged inside the dielectric layer between the gate electrode and the drain electrode, the field plate comprising field plate light vias and / or field plate light blind slots, each of the field plate light vias and / or each of the field plate light blind slots exposing a corresponding P-type doped h-BN structure in a vertical direction.
[0021] Further, the field plate light vias and / or the field plate light blind slots in the field plate are not less than the corresponding P-type doped h-BN structure.
[0022] Further, a plurality of the field plates are included, and the longitudinal positions of the field plates in the dielectric layer are sequentially raised in a direction from the gate electrode to the drain electrode.
[0023] Optionally, the P-type doped h-BN structure has a feature size ranging from 10 nm to 100 nm.
[0024] Optionally, a spacing between two adjacent P-type doped h-BN structures is not less than a feature size of the P-type doped h-BN structure.
[0025] Optionally, all the P-type doped h-BN structures are the same and uniformly distributed between the source electrode and the gate electrode and / or between the drain electrode and the gate electrode.
[0026] Optionally, the device further comprises a substrate and a buffer layer arranged between the substrate and the channel layer, the buffer layer having a thickness of 2 μm to 6 μm; the channel layer is a GaN layer having a thickness of 100 nm to 500 nm; the barrier layer is an AlGaN layer having a thickness of 10 nm to 30 nm; and the P-type doped h-BN structure has a thickness of 10 nm to 70 nm.
[0027] As described above, the light-responsive HEMT device and the preparation method thereof provided by the application form a p-hBN / n-AlGaN heterojunction by forming a P-type doped h-BN array on the barrier layer, and the built-in electric field generated by the p-hBN / n-AlGaN heterojunction causes the conduction band under the p-hBN layer to be lifted in the dark, resulting in the disappearance of the 2DEG quantum well formed by polarization induction at the AlGaN / GaN heterojunction interface, the partial conduction channel of the device is turned off, and a low dark current is achieved; under ultraviolet light, the built-in electric field near the heterojunction interface separates the photo-generated electron-hole pairs, the photo-generated holes gather at the p-hBN / n-AlGaN interface, and the photo-generated electrons are induced to the n-AlGaN / n-GaN interface, in this process, the built-in electric field gradually weakens, and finally the 2DEG recovers, the conduction channel of the device is fully turned on, a high photocurrent is achieved, and thus the optical response capability of the device is achieved. BRIEF DESCRIPTION OF DRAWINGS
[0028] Figures 1 to 13 The diagram shows the structural schematics of each step in the fabrication method of the optically responsive HEMT device according to Embodiment 1 of the present invention; wherein... Figure 4 and Figure 5 for Figure 3 A plan view, Figure 11 and Figure 12 for Figure 10 A plan view.
[0029] Component designation explanation
[0030] 10 Stacked structure 100 Channel layer 101 Barrier layer 102 Substrate 103 Buffer layer 104 P-type doped h-BN layer 11 P-type doped h-BN array 110 P-type doped h-BN structure 12 Source electrode 13 Drain electrode 14 Gate electrode 105 Dielectric layer 15 Pad 150 Pad via 151 Pad blind via 16 Field plate 160 Field plate via 161 Field plate blind via Detailed Implementation
[0031] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.
[0032] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components.
[0033] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.
[0034] In the detailed description of embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged and not to scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.
[0035] For ease of description, spatial relation terms such as “below,” “under,” “lower than,” “below,” “above,” and “upper” may be used herein to describe the relationship between one element or feature shown in the accompanying drawings and other elements or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the drawings for devices in use or operation. Furthermore, when a layer is referred to as being “between” two layers, it may be the only layer between the two layers, or there may be one or more layers in between.
[0036] In the context of this application, the structure described above the first feature may include embodiments in which the first and second features are formed in direct contact, or embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.
[0037] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.
[0038] Example 1
[0039] This embodiment provides a method for fabricating a photoresponsive HEMT device, the method comprising the following steps:
[0040] S1, providing a stacked structure, the stacked structure including a channel layer, a barrier layer located on the channel layer, and a P-type doped h-BN layer located on the barrier layer;
[0041] S2, the P-type doped h-BN layer is patterned by photolithography to obtain a P-type doped h-BN array; wherein, the P-type doped h-BN array includes at least one P-type doped h-BN structure;
[0042] S3, a source electrode, a drain electrode, and a gate electrode are formed on the barrier layer; wherein the source electrode and the drain electrode are located on opposite sides of the gate electrode, and all the P-type doped h-BN structures are disposed between the source electrode and the gate electrode and / or between the drain electrode and the gate electrode;
[0043] S4, a dielectric layer is formed on the barrier layer to cover the P-type doped h-BN array, the source electrode, the drain electrode, and the gate electrode;
[0044] S5, forming pads on the dielectric layer, wherein the pads include pad vias and / or pad blind slots, and each pad via and / or each pad blind slot exposes at least one of the P-type doped h-BN structures in the vertical direction.
[0045] The fabrication method of the photoresponsive HEMT device in this embodiment involves forming a p-hBN / n-AlGaN heterojunction by creating a p-type doped h-BN array on a barrier layer. Under dark conditions, the built-in electric field generated by the p-hBN / n-AlGaN heterojunction causes the conduction band below the p-hBN layer to rise, resulting in the disappearance of the 2DEG quantum well formed by polarization induction at the AlGaN / GaN heterojunction interface. This turns off part of the conductive channel of the device, achieving low dark current. Under ultraviolet light, the built-in electric field near the heterojunction interface separates photogenerated electron-hole pairs. Photogenerated holes accumulate at the p-hBN / n-AlGaN interface, while photogenerated electrons are induced to the n-AlGaN / n-GaN interface. During this process, the built-in electric field gradually weakens, and eventually the 2DEG recovers, turning on all the conductive channels of the device and achieving high photocurrent, thereby realizing the optical response capability of the device.
[0046] The fabrication method of the photoresponsive HEMT device of this embodiment will be described in detail below with reference to the specific accompanying drawings.
[0047] like Figure 1 As shown, step S1 is performed first, providing a stacked structure 10. The stacked structure 10 includes a channel layer 100, a barrier layer 101 on the channel layer 100, and a P-type doped h-BN layer 104 on the barrier layer 101. The material of the channel layer 100 is selected according to actual needs. When the HEMT device is a GaN-based HEMT device, the channel layer 100 is a GaN layer, with a thickness generally selected from 100nm to 500nm. The barrier layer 101 is an AlGaN layer, with a thickness generally from 10nm to 30nm. The thickness of the P-type doped h-BN layer 104 is not excessively limited and is designed according to process requirements, generally selected within the range of 10nm to 70nm. The stacked structure 10 may also include a substrate 102, such as... Figure 2 As shown, the substrate 102 can be selected from silicon, silicon carbide, sapphire, gallium nitride, etc., gallium nitride epitaxial substrates. A buffer layer 103 can be provided between the substrate 102 and the channel layer 100 to alleviate the lattice mismatch between the substrate 102 and the channel layer 100. The thickness of the buffer layer 103 is generally selected to be 2μm~6μm.
[0048] The stacked structure 10 can be fabricated using conventional epitaxial processes, such as metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE). In this embodiment, metal-organic chemical vapor deposition (MOCVD) is preferably used to fabricate the stacked structure 10. Specifically, a substrate 102 is first provided, and then the growth surface of the substrate 102 is... Figure 2The buffer layer 103, the channel layer 100, the barrier layer 101, and the P-type doped h-BN layer 104 are epitaxially grown sequentially on the upper surface of the structure.
[0049] like Figure 3 As shown, step S2 is then performed to perform photolithographic patterning on the P-type doped h-BN layer 104 to obtain a P-type doped h-BN array 11; wherein, the P-type doped h-BN array 11 includes at least one P-type doped h-BN structure 110.
[0050] The shape of the p-type doped h-BN structure 110 is not overly restricted and can be selected according to actual needs. It can be a regular shape or an irregular shape, for example, Figure 4 As shown, the P-type doped h-BN structure 110 is a regular circle, as... Figure 5 As shown, the P-type doped h-BN structure 110 is a regular rectangle. The feature size of the P-type doped h-BN structure 110 is designed according to actual needs, generally selected in the range of 10nm to 100nm. For example, when the P-type doped h-BN structure 110 is circular, the diameter is 10nm to 100nm; when the P-type doped h-BN structure 110 is square, the side length is 10nm to 100nm; and when the P-type doped h-BN structure 110 is rectangular, the shorter side length is 10nm to 100nm. The number of P-type doped h-BN structures 110 can be selected according to actual needs; there can be one or several, without excessive restrictions. In principle, the more P-type doped h-BN structures 110 there are, the lower the dark current under dark conditions and the more sensitive the response to optical signals. However, if there are too many, more two-dimensional electron gases in the electron channel will be depleted under dark conditions, which may even cause the device to shut down. In this embodiment, it is preferred that the spacing between two adjacent P-type doped h-BN structures 110 is not less than the feature size of the P-type doped h-BN structure 110. The P-type doped h-BN structures 110 can be the same or different, and can be uniformly distributed or non-uniformly distributed. Based on the convenience of process implementation, this embodiment preferably has the same P-type doped h-BN structures 110, and they are uniformly distributed between the region of the subsequently pre-formed source electrode 12 and the region of the gate electrode 14 and / or between the region of the subsequently pre-formed drain electrode 13 and the region of the gate electrode 14.
[0051] As a specific example, the method for forming the P-type doped h-BN array 11 includes:
[0052] A photoresist layer is coated on the surface of the P-type doped h-BN layer 104, and the photoresist layer is patterned to obtain a patterned photoresist layer. The exposed area of the patterned photoresist layer is defined as the area of the P-type doped h-BN structure 110. The defined area of the P-type doped h-BN structure 110 corresponds to the size, shape, and number of the pre-formed P-type doped h-BN structure 110, which will not be elaborated here. Based on the patterned photoresist layer, the P-type doped h-BN layer 104 outside the pre-formed P-type doped h-BN structure 110 is etched to the surface of the barrier layer 101, and then the patterned photoresist layer is removed to obtain the P-type doped h-BN array 11.
[0053] like Figure 6 As shown, step S3 is then performed to form a source electrode 12, a drain electrode 13, and a gate electrode 14 on the barrier layer 101; wherein the source electrode 12 and the drain electrode 13 are located on opposite sides of the gate electrode 14, and all the P-type doped h-BN structures 110 are disposed between the source electrode 12 and the gate electrode 14 and / or between the drain electrode 13 and the gate electrode 14.
[0054] As a specific example, the process of forming the source electrode 12, the drain electrode 13, and the gate electrode 14 on the barrier layer 101 is as follows: First, a photoresist layer is coated on the barrier layer 101, covering the P-type doped h-BN array 11 and the barrier layer 101. Then, the photoresist layer is patterned, exposing the surface of the barrier layer 101 in the region where the gate electrode 14 is to be formed. Then, the metal material of the gate electrode 14 is deposited on the entire surface based on the patterned photoresist layer. Then, the patterned photoresist layer and the metal material of the gate electrode 14 on it are removed, thereby forming the gate electrode 14. Following the same method, the source electrode 12 is formed on the barrier layer 101 on one side of the gate electrode 14, and the drain electrode 13 is formed on the barrier layer 101 on the other side of the gate electrode 14, so that the source electrode 12 and the drain electrode 13 are located on opposite sides of the gate electrode 14. At this time, all the P-type doped h-BN structures 110 are disposed between the source electrode 12 and the gate electrode 14 and / or between the drain electrode 13 and the gate electrode 14.
[0055] like Figure 7As shown, step S4 is then performed to form a dielectric layer 105 on the barrier layer 101, which covers the P-type doped h-BN array 11, the source electrode 12, the drain electrode 13, and the gate electrode 14. Conventional deposition processes, such as PECVD and LPCVD, can be used to form the dielectric layer 105. The material of the dielectric layer 105 is not limited and can be a silicon nitride layer or a silicon oxide layer, whichever is selected according to actual needs.
[0056] To control the peak electric field, shield the drain-end electric field, and improve the device's breakdown voltage, such as... Figures 8 to 12 As shown, after step S4, a step of forming a field plate 16 in the dielectric layer 105 between the gate electrode 14 and the drain electrode 13 is further included; wherein, the field plate 16 includes field plate optical vias 160 and / or field plate optical blind trenches 161, and each field plate optical via 160 and / or each field plate optical blind trench 161 exposes a corresponding P-type doped h-BN structure 110 in the vertical direction. Specifically, a photoresist layer is coated on the surface of the dielectric layer 105, and the photoresist layer is patterned. The patterned photoresist layer exposes the surface of the dielectric layer 105 in the area where the field plate 16 is to be formed. The field plate 16 material is deposited on the entire surface based on the patterned photoresist layer, so that the field plate 16 material fills the surface of the dielectric layer 105 in the area where the field plate 16 is to be formed. The patterned photoresist layer and the field plate 16 material on it are removed, thereby forming the field plate 16. Figure 9 As shown. Since the field plate 16 is made of metal, when the P-type doped h-BN structure 110 is located below the field plate 16 in the vertical direction, light cannot pass through the field plate 16 and illuminate the P-type doped h-BN structure 110. Therefore, it is necessary to fabricate the field plate optical via 160 and / or the field plate optical blind groove 161 on the field plate 16, such as... Figure 10 As shown, each of the field plate optical vias 160 and / or each of the field plate optical blind slots 161 exposes a corresponding P-type doped h-BN structure 110 in the vertical direction. Preferably, the field plate optical vias 160 and / or the field plate optical blind slots 161 in the field plate 16 are not smaller than the corresponding P-type doped h-BN structure 110, so that the entire P-type doped h-BN structure 110 can receive light. As an example, the field plate optical vias 160... The method for fabricating the field plate optical blind trench 161 is as follows: a photoresist layer is coated on the surface of the obtained structure, and the photoresist layer is patterned. The patterned photoresist layer exposes the surface of the field plate 16 in the region where the field plate optical via 160 and / or the field plate optical blind trench 161 are to be formed. Based on the patterned photoresist layer, the exposed field plate 16 is etched to the surface of the dielectric layer 105, and then the patterned photoresist layer is removed, thereby forming the field plate optical via 160. Figure 11As shown, and / or the field plate optical blind slot 161, as Figure 12 As shown. As a specific example, the device includes a plurality of said field plates 16, and in the direction from the gate electrode 14 to the drain electrode 13, the longitudinal position of the field plates 16 in the dielectric layer 105 increases sequentially, as shown below. Figure 8 As shown, the specific formation process is as follows: the dielectric layer 105 is deposited on the surface of the bottommost field plate 16 and the dielectric layer 105. Then, a second field plate 16 and its field plate optical vias 160 and / or field plate optical blind grooves 161 are formed on the dielectric layer 105 using photolithography. This process is repeated to form other field plates 16 and their field plate optical vias 160 and / or field plate optical blind grooves 161. Finally, the dielectric layer 105 is deposited on the last field plate 16 and the surface of the dielectric layer 105 thereon to cover the last field plate 16.
[0057] like Figure 13 As shown, step S5 is then performed, forming pads 15 on the dielectric layer 105. Each pad 15 includes a via 150 and / or a blind slot 151, with each via 150 and / or blind slot 151 exposing at least one P-type doped h-BN structure 110 in the vertical direction. Specifically, the pads 15 are first fabricated in a predetermined area on the dielectric layer 105. When a P-type doped h-BN structure 110 is located below the pad 15 in the vertical direction, the via 150 and / or the blind slot 151 need to be fabricated at the corresponding position to expose at least one P-type doped h-BN structure 110 in the vertical direction, allowing light to reach the P-type doped h-BN structure 110.
[0058] Example 2
[0059] This embodiment provides a photoresponsive HEMT device, which can be fabricated using the method described in Embodiment 1. Therefore, the materials and fabrication processes of the photoresponsive HEMT device can be found in Embodiment 1. Of course, other fabrication processes can also be used to fabricate the photoresponsive HEMT device as needed, as long as the photoresponsive HEMT device can be formed. The beneficial effects achievable by this photoresponsive HEMT device are described in Embodiment 1 and will not be repeated below.
[0060] like Figure 13 As shown, the HEMT device includes:
[0061] Channel layer 100;
[0062] A barrier layer 101 is disposed on the channel layer 100;
[0063] A source electrode 12, a drain electrode 13, and a gate electrode 14 are disposed on the barrier layer 101; wherein the source electrode 12 and the drain electrode 13 are located on opposite sides of the gate electrode 14.
[0064] P-type doped h-BN array 11 includes at least one P-type doped h-BN structure 110, and all the P-type doped h-BN structures 110 are disposed on the barrier layer 101 between the source electrode 12 and the gate electrode 14 and / or between the drain electrode 13 and the gate electrode 14.
[0065] A dielectric layer 105 is disposed on the barrier layer 101 and covers the P-type doped h-BN array 11, the source electrode 12, the drain electrode 13 and the gate electrode 14;
[0066] A pad 15 is disposed on the dielectric layer 105, wherein the pad 15 includes a pad via 150 and / or a pad blind groove 151, and each of the pad via 150 and / or each of the pad blind grooves 151 exposes at least one of the P-type doped h-BN structures 110 in the vertical direction.
[0067] As an example, it also includes: a field plate 16 disposed inside the dielectric layer 105 between the gate electrode 14 and the drain electrode 13, the field plate 16 including field plate optical vias 160 and / or field plate optical blind slots 161, each of the field plate optical vias 160 and / or each of the field plate optical blind slots 161 exposing a corresponding P-type doped h-BN structure 110 in the vertical direction.
[0068] As an example, the field plate optical via 160 and / or the field plate optical blind slot 161 in the field plate 16 are not smaller than the corresponding P-type doped h-BN structure 110.
[0069] As a specific example, the field plates 16 are provided, and in the direction from the gate electrode 14 to the drain electrode 13, the longitudinal position of the field plates 16 in the dielectric layer 105 is raised sequentially.
[0070] As an example, the feature size range of the P-type doped h-BN structure 110 is 10 nm to 100 nm.
[0071] As a specific example, the spacing between two adjacent P-type doped h-BN structures 110 is not less than the feature size of the P-type doped h-BN structure 110.
[0072] As an example, all the P-type doped h-BN structures 110 are identical and are uniformly distributed between the source electrode 12 and the gate electrode 14 and / or between the drain electrode 13 and the gate electrode 14.
[0073] As an example, the device further includes a substrate 102 and a buffer layer 103, wherein the buffer layer 103 is disposed between the substrate 102 and the channel layer 100, and has a thickness of 2μm to 6μm; the channel layer 100 is a GaN layer with a thickness of 100nm to 500nm; the barrier layer 101 is an AlGaN layer with a thickness of 10nm to 30nm; and the P-type doped h-BN structure 110 has a thickness of 10nm to 70nm.
[0074] In summary, the present invention provides a photoresponsive HEMT device and its fabrication method. By forming a p-type doped h-BN array on a barrier layer to form a p-hBN / n-AlGaN heterojunction, under dark conditions, the built-in electric field generated by the p-hBN / n-AlGaN heterojunction causes the conduction band below the p-hBN layer to rise, resulting in the disappearance of the 2DEG quantum well formed by polarization induction at the AlGaN / GaN heterojunction interface. This turns off part of the conductive channel of the device, achieving low dark current. Under ultraviolet light, the built-in electric field near the heterojunction interface separates photogenerated electron-hole pairs. Photogenerated holes accumulate at the p-hBN / n-AlGaN interface, while photogenerated electrons are induced to the n-AlGaN / n-GaN interface. During this process, the built-in electric field gradually weakens, and eventually the 2DEG recovers, and all the conductive channels of the device are turned on, achieving high photocurrent and thus realizing the optical response capability of the device. Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.
[0075] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.
Claims
1. A photoresponsive HEMT device, characterized in that, The HEMT device includes: Channel layer; A barrier layer is disposed on the channel layer; A source electrode, a drain electrode, and a gate electrode are disposed on the barrier layer; wherein the source electrode and the drain electrode are located on opposite sides of the gate electrode. A P-type doped h-BN array includes at least one P-type doped h-BN structure, and all the P-type doped h-BN structures are disposed on the barrier layer between the source electrode and the gate electrode and / or between the drain electrode and the gate electrode; A dielectric layer is disposed on the barrier layer and covers the P-type doped h-BN array, the source electrode, the drain electrode, and the gate electrode; A pad is disposed on the dielectric layer, wherein the pad includes a pad via and / or a pad blind slot, and each of the pad vias and / or the pad blind slots exposes at least one of the P-type doped h-BN structures in the vertical direction.
2. The photoresponsive HEMT device according to claim 1, characterized in that, Also includes: A field plate is disposed inside the dielectric layer between the gate electrode and the drain electrode. The field plate includes a field plate optical via and / or a field plate optical blind trench. Each field plate optical via and / or each field plate optical blind trench exposes a corresponding P-type doped h-BN structure in the vertical direction.
3. The photoresponsive HEMT device according to claim 2, characterized in that: It includes a plurality of field plates, and the longitudinal position of the field plates in the dielectric layer increases sequentially in the direction from the gate electrode to the drain electrode.
4. The photoresponsive HEMT device according to claim 2, characterized in that: The field plate optical vias and / or the field plate optical blind slots in the field plate are not smaller than the corresponding P-type doped h-BN structure.
5. The photoresponsive HEMT device according to claim 1, characterized in that: The characteristic size range of the P-type doped h-BN structure is 10 nm to 100 nm.
6. The photoresponsive HEMT device according to claim 1, characterized in that: The spacing between two adjacent P-type doped h-BN structures is not less than the feature size of the P-type doped h-BN structure.
7. The photoresponse HEMT device according to claim 1, characterized in that: All of the described P-type doped h-BN structures are identical and are uniformly distributed between the source electrode and the gate electrode and / or between the drain electrode and the gate electrode.
8. The photoresponsive HEMT device according to claim 1, characterized in that: The device further includes a substrate and a buffer layer, wherein the buffer layer is disposed between the substrate and the channel layer and has a thickness of 2μm to 6μm; the channel layer is a GaN layer with a thickness of 100nm to 500nm; the barrier layer is an AlGaN layer with a thickness of 10nm to 30nm; and the thickness of the P-type doped h-BN structure is 10nm to 70nm.
9. A method for fabricating a photoresponsive HEMT device, characterized in that, The preparation method includes the following steps: S1, providing a stacked structure, the stacked structure including a channel layer, a barrier layer located on the channel layer, and a P-type doped h-BN layer located on the barrier layer; S2, the P-type doped h-BN layer is patterned by photolithography to obtain a P-type doped h-BN array; wherein, the P-type doped h-BN array includes at least one P-type doped h-BN structure; S3, a source electrode, a drain electrode, and a gate electrode are formed on the barrier layer; wherein the source electrode and the drain electrode are located on opposite sides of the gate electrode, and all the P-type doped h-BN structures are disposed between the source electrode and the gate electrode and / or between the drain electrode and the gate electrode; S4, a dielectric layer is formed on the barrier layer to cover the P-type doped h-BN array, the source electrode, the drain electrode, and the gate electrode; S5, forming pads on the dielectric layer, wherein the pads include pad vias and / or pad blind slots, and each pad via and / or each pad blind slot exposes at least one of the P-type doped h-BN structures in the vertical direction.
10. The method for fabricating a photoresponsive HEMT device according to claim 9, characterized in that: Step S4 is followed by a step of forming a field plate in the dielectric layer between the gate electrode and the drain electrode; wherein the field plate includes a field plate optical via and / or a field plate optical blind trench, and each field plate optical via and / or each field plate optical blind trench exposes a corresponding P-type doped h-BN structure in the vertical direction.