GaN pressure sensor preparation method and device
By optimizing the structure of the GaN pressure sensor through a multilayer GaN/AlGaN channel structure and a multi-ring source design, the problems of low sensor sensitivity and poor stability are solved, achieving high sensitivity and long-term stability, making it suitable for high temperature and high pressure environments.
Patent Information
- Application Number
- CN202511692684.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-18
- Publication Date
- 2026-02-13
AI Technical Summary
Existing GaN pressure sensors suffer from low sensitivity, small current signal change rate, and limited contact area between traditional electrode structures and channels, resulting in poor detection accuracy and stability, making it difficult to meet the application requirements in harsh environments such as high temperature and high pressure.
A GaN pressure sensor with high sensitivity and stability is fabricated by adopting a multi-layer GaN/AlGaN channel structure, a multi-ring source design, and combining a substrate groove and a separator structure to optimize the source and drain materials and morphology.
It improves the sensitivity of the pressure sensor by 3-5 times, ensuring a long-term working accuracy drift rate of ≤0.5%/year, meeting the application requirements in harsh environments.
Smart Images
Figure CN121531745A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of GaN pressure sensor technology, specifically to a method for fabricating a GaN pressure sensor and a device thereof. Background Technology
[0002] Pressure sensors are core sensing components in industrial automation and intelligent equipment. Traditional pressure sensors are mostly based on silicon (Si) materials, relying on the piezoresistive effect of silicon to achieve pressure-to-electrical signal conversion. However, silicon materials have limitations such as narrow bandgap (1.12eV), poor high-temperature resistance (long-term operating temperature ≤150℃), and low breakdown field strength (~3MV / cm). Under harsh environments such as high temperature and high pressure, they are prone to performance degradation and shortened lifespan, making it difficult to meet the stringent requirements of aerospace, new energy vehicles and other fields.
[0003] To address the aforementioned issues, wide-bandgap semiconductor materials (such as GaN) have become the preferred solution for next-generation sensors. GaN materials possess advantages such as a wide bandgap (3.4 eV), high temperature resistance (long-term operating temperature ≥300℃), high breakdown field strength (~3.3 MV / cm), and high electron mobility. However, existing GaN pressure sensors mostly employ a single-layer channel structure, which suffers from low pressure response sensitivity and a small current signal change rate. Furthermore, the limited contact area between traditional electrode structures (such as strip-shaped source-drain electrodes) and the channel easily leads to uneven current distribution, further affecting the sensor's detection accuracy and stability.
[0004] Therefore, there is an urgent need to design a GaN pressure sensor with optimized structure. Through the synergistic design of multi-channel and special electrode structure, the problems of low sensitivity and poor environmental adaptability of existing devices can be solved. Summary of the Invention
[0005] The purpose of this section is to outline some aspects of the embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.
[0006] In view of the problems existing in the current GaN pressure sensor fabrication method and device, the present invention is proposed.
[0007] Therefore, the purpose of this invention is to provide a GaN pressure sensor device that achieves high sensitivity, high stability, and wide temperature range pressure detection by optimizing the substrate structure, source and drain materials and morphology, and channel layer stacking method, thereby meeting the application requirements in harsh environments.
[0008] To address the aforementioned technical problems, according to one aspect of the present invention, the present invention provides the following technical solution:
[0009] A GaN pressure sensor device comprising a substrate;
[0010] A source electrode is disposed above the substrate, a drain electrode is disposed above the source electrode, and a gate electrode and a channel structure are disposed between the drain electrode and the source electrode. The channel structure comprises a GaN layer and an AlGaN barrier layer.
[0011] The source electrode is composed of multiple ring structures, which are connected by a connecting structure. The inner and outer edges of the ring structures are provided with channel structures, and the multiple channel structures are provided with partitions.
[0012] In a preferred embodiment of the GaN pressure sensor device described in this invention, the lower surface of the substrate has a groove, and the upper surface is sealed to the source electrode.
[0013] In a preferred embodiment of the GaN pressure sensor device described in this invention, the source and the drain are both Ti / Al / Ni / Au stacked layers, and the source and the drain cover all the multilayer stacked GaN layers and AlGaN barrier layers.
[0014] In a preferred embodiment of the GaN pressure sensor device described in this invention, the number of stacked GaN layers and AlGaN barrier layers is 3 to 9, the GaN layer is located at the outer edge of the ring structure, the AlGaN barrier layer is located inside the GaN layer, and the GaN layer is located outside the partition.
[0015] In a preferred embodiment of the GaN pressure sensor device described in this invention, the thickness of the GaN layer (201) is 20-200 nm, and the thickness of the AlGaN barrier layer (202) is 5-50 nm.
[0016] In a preferred embodiment of the GaN pressure sensor device described in this invention, a channel is formed between the source electrode and the GaN layer and the AlGaN barrier layer, and the drain electrode is sealed to the top of the channel.
[0017] In a preferred embodiment of the GaN pressure sensor device described in this invention, the gate is a Ni / Au stack.
[0018] As a preferred embodiment of the GaN pressure sensor fabrication method described in this invention, the substrate pretreatment involves sequentially ultrasonically cleaning with acetone, ethanol, and deionized water (10-15 min each), followed by immersion in dilute hydrochloric acid (5%-10%) for 5 min to remove impurities and oxides; and fabricating grooves (5-20 μm deep) on the lower surface of the substrate using ICP etching.
[0019] Channel structure fabrication: GaN / AlGaN layers are epitaxially grown using MOCVD equipment (growth temperature 900-1050℃), and spacers are fabricated by photolithography and ICP etching. The process is repeated to form 3-9 stacked channels.
[0020] Source fabrication: Photolithography defines a multi-ring pattern, electron beam evaporation / magnetron sputtering deposits a Ti / Al / Ni / Au stack, rapid thermal annealing (450-550℃, 30-60s) after photoresist stripping, and PECVD deposition of a Si3N4 / SiO2 insulating layer to achieve substrate-source sealing.
[0021] Channel and drain fabrication: Photolithography and etching are used to fabricate the channel between the source and channel layers. Photolithography defines the drain pattern and deposits a metal stack of the same material. After annealing, the channel is sealed and ohmic contact is achieved.
[0022] Gate fabrication: Photolithography defines the gate pattern, Ni / Au stack is deposited and stripped to form Schottky contacts.
[0023] Post-processing: PECVD deposition of passivation layer (150-200nm Si3N4), etching of electrode windows to complete device fabrication.
[0024] Compared with the prior art, the beneficial effects of the present invention are:
[0025] High sensitivity: The multilayer GaN / AlGaN channel structure increases the 2DEG density, and the multi-ring source expands the pressure contact area. These two factors work synergistically to improve the current change rate, resulting in a 3-5 times higher pressure sensitivity compared to traditional single-layer structures. Structural stability: Separators between adjacent channels prevent current crosstalk, and the substrate groove and drain closed-channel design reduce pressure transmission losses, ensuring long-term operating accuracy (drift rate ≤0.5% / year). Attached Figure Description
[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:
[0027] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the present invention;
[0028] Figure 2 This is a schematic diagram of the overall bottom view of the present invention;
[0029] Figure 3 This is a three-dimensional structural diagram of the channel structure of the present invention;
[0030] Figure 4 This is a schematic diagram of the source pole structure of the present invention viewed from below.
[0031] In the figure: 100 substrate, 101 trench, 110 source, 120 drain, 130 gate, 140 channel, 150 channel structure, 151 GaN layer, 152 AlGaN barrier layer, 160 separator. Detailed Implementation
[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0033] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.
[0034] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.
[0035] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.
[0036] This invention provides the following technical solution: a method for fabricating a GaN pressure sensor and a device. During use, it exhibits high sensitivity: the multilayer GaN / AlGaN channel structure increases the 2DEG density, and the multi-ring source expands the pressure contact area; both synergistically improve the current change rate, resulting in a 3-5 times improvement in pressure sensitivity compared to traditional single-layer structures. Structural stability: separators between adjacent channels prevent current crosstalk; the substrate groove and drain closed channel design reduce pressure transmission losses, ensuring long-term operating accuracy (drift rate ≤0.5% / year).
[0037] Figures 1-4 The diagram shown is a structural schematic of the first embodiment of a GaN pressure sensor fabrication method and device according to the present invention. Please refer to [link / reference]. Figures 1-4 This embodiment discloses a GaN pressure sensor fabrication method and device, the main body of which includes a substrate 100, a source 110, a drain 120, a gate 130, a channel structure 150, and a separator 160. The positions and connections of each component are as follows:
[0038] Substrate 100: As the support substrate for the device, it is made of materials such as sapphire, SiC or Si that are suitable for GaN epitaxial growth; a groove 101 is formed on the lower surface of the substrate 100 (to enhance pressure transmission efficiency), and the upper surface is sealed to the source 110 through an insulating layer (to prevent external impurities from entering).
[0039] Source 110: Located above substrate 100, it adopts a multi-ring structure design, with multiple ring structures connected by a strip-shaped connection structure; the source 110 is made of Ti / Al / Ni / Au metal stack (thicknesses of 20-30nm / 100-150nm / 30-40nm / 50-80nm respectively), and completely covers all multi-layer stacked channel structures 150.
[0040] Drain 120: Located above source 110, made of the same material as source 110 (Ti / Al / Ni / Au stack), covering all channel structures 150; a gap is formed between drain 120 and source 110 to set gate 130 and channel structure 150, and the bottom of drain 120 seals the channel 140 between source 110 and channel layer (to prevent dielectric leakage in channel 140).
[0041] Channel structure 150: Located in the gap between drain 120 and source 110, it is formed by alternating stacking of GaN layer 151 and AlGaN barrier layer 152 (3-9 layers); wherein, GaN layer 151 (thickness 20-200nm) is located at the outer edge of the annular source 110, and AlGaN barrier layer 152 (thickness 5-50nm, Al composition 20%-30%) is located inside GaN layer 151. The two form a heterojunction to generate a two-dimensional electron gas (2DEG) to realize current conduction.
[0042] Separator 160: Located between multiple channel structures 150, it is made of insulating GaN / AlGaN etch residue layer, with a height consistent with the thickness of a single channel layer, and is used to separate adjacent channels and avoid current crosstalk.
[0043] Gate 130: Located above the channel region between drain 120 and source 110, it is made of Ni / Au stack (thickness 30-40nm / 50-80nm), aligned with the middle region of multilayer channel structure 150. By adjusting the gate voltage, the concentration of 2DEG in the channel is controlled to realize current switching and sensitivity adjustment.
[0044] Channel 140: Formed between source 110 and channel layer, it is a strip or ring structure (5-10μm wide) used to transmit medium (such as gas or liquid) under pressure, and is sealed by drain 120 to form a sealed chamber to ensure that the pressure is accurately applied to the channel layer.
[0045] Preparation process:
[0046] Substrate 100 selection and cleaning: Select a substrate 100 that is compatible with GaN epitaxy, such as sapphire, SiC or Si, and perform ultrasonic cleaning in sequence with acetone, ethanol and deionized water (10-15 min each) to remove surface oil and impurities; then soak it in dilute hydrochloric acid (concentration 5%-10%) for 5 min to neutralize residual oxides, and finally blow it dry with nitrogen for later use.
[0047] Etching of the groove 101 on the substrate 100: The groove 101 pattern is defined by photolithography on the lower surface of the substrate 100 using inductively coupled plasma (ICP) etching technology. The etching depth is set according to the pressure sensitivity requirements of the device (usually 5-20μm). After etching, the photoresist is removed to complete the pretreatment of the substrate 100.
[0048] Epitaxial growth of the substrate: The pretreated substrate 100 is placed in a metal-organic chemical vapor deposition (MOCVD) apparatus, and a GaN layer 151 and an AlGaN barrier layer 152 are epitaxially grown sequentially on the upper surface of the substrate 100.
[0049] GaN layer 151: growth temperature 950-1050℃, growth rate 50-100nm / h, thickness controlled at 20-200nm, serving as the outer layer of the channel;
[0050] AlGaN barrier layer 152: Continues to grow on GaN layer 151 at a growth temperature of 900-1000℃, with Al composition controlled at 20%-30% and thickness of 5-50nm, serving as the inner layer of the channel.
[0051] Layer spacer 160 fabrication: The pattern of spacer 160 is defined by photolithography. The AlGaN barrier layer 152 and part of the GaN layer 151 in the target area are removed by ICP etching to form an insulating spacer 160 with a height consistent with the thickness of a single channel layer. The photoresist is removed after etching.
[0052] Multi-layer channel stacking: Repeat the epitaxial growth of the bottom layer and the preparation of the spacer 160 until a 3-9 layer GaN / AlGaN channel structure 150 is formed, with each GaN layer 151 located on the outer edge of the annular structure and the AlGaN barrier layer 152 located on the inner side, and the spacer 160 uniformly distributed between the multi-layer channels.
[0053] Source 110 pattern definition: A multi-ring source 110 pattern is defined on the surface of the multi-layer channel structure 150 using photolithography, ensuring that the inner edge and outer edge of the ring correspond to the inner side of the AlGaN barrier layer 152 and the outer side of the GaN layer 151, respectively, and that the pattern covers all stacked channel layers.
[0054] Channel 140 etching: The channel 140 pattern between the source 110 and the channel layer is defined by photolithography. The local insulating layer below the source 110 and the surface layer of the channel layer are removed by ICP etching to form a strip or ring channel 140 (5-10μm wide) connecting the source 110 region. The photoresist is removed after etching.
[0055] Drain 120 pattern definition and metal deposition: The drain 120 pattern is defined by photolithography above the source 110 to ensure that the drain 120 covers the top of the channel 140; Ti / Al / Ni / Au stack is deposited using the same process as the source 110 to cover all stacked channel layers and achieve closure of the top of the channel 140.
[0056] Drain 120 ohm contact formation: Repeated rapid thermal annealing process (parameters same as source 110) to enhance the electrical connection and sealing between drain 120 and channel layer and channel 140.
[0057] Ti / Al / Ni / Au stack deposition: Ti (20-30nm), Al (100-150nm), Ni (30-40nm), and Au (50-80nm) metal stacks are deposited sequentially using electron beam evaporation or magnetron sputtering techniques, ensuring that the stacks completely cover the lithographically defined annular region.
[0058] Source 110 pattern stripping: The substrate 100 is immersed in photoresist stripping solution to remove the photoresist not covered by metal, forming a multi-ring source 110; then rapid thermal annealing (temperature 450-550℃, time 30-60s) is performed to enhance the ohmic contact between the source 110 and the channel layer.
[0059] Substrate 100-Source 110 Sealing: Plasma-enhanced chemical vapor deposition (PECVD) technology is used to deposit a Si3N4 or SiO2 insulating layer (100-200nm thick) on the upper surface of substrate 100 (the area around source 110) to achieve a sealed connection between the upper surface of substrate 100 and source 110.
[0060] Gate 130 pattern definition: The gate 130 pattern (2-5μm wide) is defined in the channel region between the drain 120 and the source 110 using photolithography, ensuring that the gate 130 is aligned with the middle region of the multilayer channel structure 150.
[0061] Ni / Au stack deposition: Ni (30-40nm) / Au (50-80nm) metal stack is deposited using electron beam evaporation technology to cover the gate 130 region defined by photolithography.
[0062] Gate 130 pattern stripping: Immersion in stripping solution removes excess photoresist, forming the gate 130 between the drain and source; no additional annealing is required, directly forming the Schottky contact.
[0063] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the features in the disclosed embodiments can be combined with each other in any manner. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.
Claims
1. A GaN pressure sensor device, characterized in that: Including substrate (100); A source electrode (110) is disposed above the substrate (100), a drain electrode (120) is disposed above the source electrode (110), a gate electrode (130) and a channel structure (150) are disposed between the drain electrode (120) and the source electrode (110), and the channel structure (150) comprises a GaN layer (151) and an AlGaN barrier layer (152); The source electrode (110) is composed of multiple ring structures, and the multiple ring structures are connected by a connecting structure. The inner and outer edges of the ring structures are provided with channel structures (150), and the multiple channel structures (150) are provided with partitions (160).
2. The GaN pressure sensor device according to claim 1, characterized in that: The substrate (100) has a groove (101) on its lower surface and its upper surface is sealed to the source electrode (110).
3. The GaN pressure sensor device according to claim 1, characterized in that: The source (110) and the drain (120) are both Ti / Al / Ni / Au stacked layers, and the source (110) and the drain (120) cover all the multilayer stacked GaN layers (151) and AlGaN barrier layers (152).
4. The GaN pressure sensor device according to claim 1, characterized in that: The number of stacked GaN layers (151) and AlGaN barrier layers (152) is 3 to 9. The GaN layer (151) is located at the outer edge of the ring structure, the AlGaN barrier layer (152) is located inside the GaN layer (151), and the GaN layer (151) is located outside the partition (160).
5. A GaN pressure sensor device according to claim 1, characterized in that: The thickness of the GaN layer (151) (201) is 20-200 nm, and the thickness of the AlGaN barrier layer (152) (202) is 5-50 nm.
6. A GaN pressure sensor device according to claim 1, characterized in that: A channel (140) is formed between the source (110), the GaN layer (151), and the AlGaN barrier layer (152), and the drain (120) is closed to the top of the channel (140).
7. A GaN pressure sensor device according to claim 1, characterized in that: The gate (130) is a Ni / Au stack.
8. A method for fabricating a GaN pressure sensor according to any one of claims 1-7, characterized in that: Substrate (100) pretreatment: ultrasonically cleaned sequentially with acetone, ethanol and deionized water (10-15 min each), and soaked in dilute hydrochloric acid (5%-10%) for 5 min to remove impurities and oxides; grooves (101) (depth 5-20 μm) are prepared on the lower surface of substrate (100) by ICP etching. Channel structure (150) fabrication: GaN / AlGaN layer (151) is epitaxially grown using MOCVD equipment (growth temperature 900-1050℃), and spacer (160) is fabricated by photolithography + ICP etching. The steps are repeated to form 3-9 stacked channels.
9. Source (110) fabrication: Photolithography defines a multi-ring pattern, electron beam evaporation / magnetron sputtering deposits Ti / Al / Ni / Au stack, after stripping the photoresist, rapid thermal annealing (450-550℃, 30-60s), PECVD deposits Si3N4 / SiO2 insulating layer to achieve substrate (100)-source (110) sealing. Channel (140) and drain (120) fabrication: Photolithography + ICP etching to fabricate the channel (140) between the source (110) and the channel layer, photolithography to define the drain (120) pattern and deposit a metal stack of the same material, and after annealing to achieve channel (140) sealing and ohmic contact.
10. Gate (130) fabrication: The gate (130) pattern is defined by photolithography, Ni / Au stack is deposited and stripped to form Schottky contacts. Post-processing: PECVD deposition of passivation layer (150-200nm Si3N4), etching of electrode windows to complete device fabrication.