A t-shaped anode gaN schottky temperature sensor and a preparation method thereof

Abstract

The application discloses a T-shaped anode GaN Schottky temperature sensor, which comprises a substrate, a nucleation layer, a buffer layer, a channel layer, an AlN insertion layer and a barrier layer which are stacked from bottom to top; a semicircular ring-shaped P-type GaN layer is stacked on one side of the barrier layer; a first passivation layer covers the upper surface of the barrier layer except the P-type GaN layer; a second passivation layer covers the upper surfaces of the P-type GaN layer and the first passivation layer; a semicircular anode groove is located in the inner ring of the semicircular ring-shaped P-type GaN layer; a ring-shaped cathode groove surrounds the semicircular ring-shaped P-type GaN layer; the T-shaped anode is an anode Schottky contact metal; and the ring-shaped cathode is a cathode ohmic contact metal. The temperature sensor provided by the application can adjust and expand the sub-threshold region, improve the measurement accuracy of heterojunction temperature, and meanwhile, the advantages of high linearity, low on-voltage and low reverse leakage current are maintained.

Description

Technical Field

[0001] This invention belongs to the field of temperature sensors, specifically relating to a T-type anode GaN Schottky temperature sensor and its fabrication method. Background Technology

[0002] In recent years, GaN materials have gained a foothold in the market due to their advantages such as large bandgap, high breakdown electric field, radiation resistance, and high temperature resistance. HEMT (High Electron Mobility Transistor) devices fabricated with GaN have been widely used due to their excellent switching characteristics and voltage withstand capability. GaN-based HEMT devices are core components in high-frequency power conversion applications and have seen extensive use in electric vehicles and new energy fields in recent years. However, new applications place higher reliability requirements on GaN-based HEMT devices. During operation, the heterojunction temperature of GaN-based HEMT devices rises, and the electrical performance of the two-dimensional electron gas (2DEG) channel deteriorates due to temperature effects. Long-term operation at high temperatures may lead to device degradation and reduced lifespan. To reduce or avoid device failures caused by high temperatures, real-time monitoring of the temperature of GaN-based power devices using integrated temperature sensors can effectively protect the devices and prevent failure of GaN-based HEMT devices due to excessively high temperatures. However, currently available GaN temperature sensors have relatively low temperature monitoring sensitivity and cannot yet meet the application requirements of GaN-based HEMT devices. Summary of the Invention

[0003] To address the aforementioned problems in the prior art, this invention provides a T-type anode GaN Schottky temperature sensor and its fabrication method.

[0004] The technical problem to be solved by this invention is achieved through the following technical solution:

[0005] In a first aspect, the present invention provides a T-type anode GaN Schottky temperature sensor comprising:

[0006] The substrate, nucleation layer, buffer layer, channel layer, AlN insertion layer and barrier layer are stacked from bottom to top;

[0007] A semi-circular P-type GaN layer is stacked on one side above the barrier layer, with its arc curving towards the center of the device.

[0008] A first passivation layer covers the area on the upper surface of the barrier layer except for the semi-circular P-type GaN layer; the first passivation layer and the semi-circular P-type GaN layer have the same thickness.

[0009] The second passivation layer covers the upper surface of the semi-circular annular P-type GaN layer and the first passivation layer;

[0010] The semi-cylindrical anode groove is located inside the ring of the semi-circular P-type GaN layer; the depth of the semi-cylindrical anode groove is equal to the sum of the thicknesses of the second passivation layer and the semi-circular P-type GaN layer.

[0011] An annular cathode groove surrounds the semi-circular annular P-type GaN layer and is spaced a certain distance from the semi-circular annular P-type GaN layer. The depth of the annular cathode groove is greater than the sum of the thicknesses of the second passivation layer, the first passivation layer, and the barrier layer.

[0012] The T-shaped anode is a Schottky metal anode, which fills the semi-cylindrical anode groove and overlaps the second passivation layer around the semi-cylindrical anode groove;

[0013] The annular cathode is a cathode ohmic metal that fills the annular cathode groove and overlaps the second passivation layer around the annular cathode groove.

[0014] In one embodiment, the inner wall of the annular cathode groove is doped with arsenic ions.

[0015] In one embodiment, hydrogen ions are introduced into the semi-circular annular P-type GaN layer.

[0016] In one embodiment, the first passivation layer comprises a Si3N4 passivation layer.

[0017] In one embodiment, the second passivation layer comprises a SiO2 passivation layer.

[0018] In one embodiment, the anode Schottky metal comprises Ti, Al, and Au.

[0019] In one embodiment, the cathode ohmic metal includes Ti, Al, Ni, and Au.

[0020] Secondly, this invention provides a method for fabricating a T-type anode GaN Schottky temperature sensor, comprising:

[0021] Step 1: Fabrication of an epitaxial wafer; the epitaxial wafer comprises, from bottom to top, a substrate, a nucleation layer, a buffer layer, a channel layer, an AlN insertion layer, a barrier layer, and a P-type GaN layer;

[0022] Step 2: Define a semi-circular region on one side of the surface of the P-type GaN layer, and etch downwards into the region outside the semi-circular region, extending the etching depth to the barrier layer; wherein, the arc of the semi-circular region bends toward the center of the epitaxial wafer.

[0023] Step 3: Deposit the first passivation layer on the surface of the current sample, with the same thickness as the P-type GaN layer.

[0024] Step 4: Deposit a second passivation layer on the surface of the current sample;

[0025] Step 5: Define an anode region on the surface of the second passivation layer above the remaining P-type GaN layer, and etch the anode region downwards to the barrier layer to form a semi-cylindrical anode groove. The remaining P-type GaN layer is a semi-circular annular P-type GaN layer.

[0026] Step 6: Deposit Schottky metal in the semi-cylindrical anode groove and overlap the Schottky metal with the second passivation layer around the anode groove to form a T-type anode with Schottky contact;

[0027] Step 7: Define an annular cathode region around the semi-circular region on the surface of the second passivation layer, and etch the annular cathode region downwards to the depth of the etching extending into the channel layer to form an annular cathode groove; the annular cathode region is spaced a certain distance from the semi-circular region;

[0028] Step 8: Deposit ohmic metal in the annular cathode groove to form an annular cathode with ohmic contact, thus obtaining the prepared T-type anode GaN Schottky temperature sensor.

[0029] In one embodiment, prior to step eight, the method further includes doping the inner wall of the annular cathode groove with arsenic ions.

[0030] In one embodiment, prior to step two, the method further includes:

[0031] Si3N4 was deposited on the surface of the prepared P-type GaN layer for passivation;

[0032] The Si3N4 layer deposited on the surface of the P-type GaN layer is removed by a hydrogen ion wet process to introduce hydrogen ions into the P-type GaN layer.

[0033] The T-type anode GaN Schottky temperature sensor and its fabrication method provided by this invention have the following beneficial effects:

[0034] First, the T-type anode GaN Schottky temperature sensor provided by this invention uses a semi-cylindrical anode electrode. The semi-circular electrode electric field generated by the semi-cylindrical anode electrode is not as concentrated as that of a rectangle, which can reduce the problem of large boundary electric field peaks, thereby alleviating electric field spikes and protecting the Schottky contact of the anode. At the same time, the semi-cylindrical anode electrode can also reduce reverse leakage current and increase forward conduction current, so that the temperature sensor of this invention requires a lower anode voltage and generates less power consumption under the same current.

[0035] Secondly, retaining the semi-circular P-type GaN layer not only depletes the two-dimensional electron gas beneath the P-type GaN layer, thus preventing the device from being constantly on, but also allows for better control of the temperature sensor's on / off state, thereby avoiding interference with the normal operation of other devices in an integrated environment. Since the temperature sensor itself is a Schottky barrier diode, placing the P-type GaN layer under the anode electrode would affect the normal conduction of the Schottky diode. The temperature sensor provided by this invention forms the P-type GaN layer into a semi-circular ring that fits the semi-circular anode electrode, keeping the P-type GaN layer as far away as possible from the contact interface between the metal and the barrier layer, reducing the influence of the P-type GaN layer on the Schottky barrier, while simultaneously allowing the P-type GaN layer to serve as the equivalent series resistance of the temperature sensor.

[0036] Finally, applying a voltage to the T-shaped anode of the temperature sensor provided by this invention will result in the following three operating stages: 1. The Schottky barrier is not conducting, and electrons are about to cross the Schottky barrier; 2. The Schottky barrier is conducting, but the current is very small, and the P-type GaN layer is equivalent to a series resistor, playing a role in conductivity modulation; 3. The conductivity modulation effect of the P-type GaN layer is exhausted, the 2DEG is completely released, and full conduction occurs. As can be seen from the performance of temperature sensor devices, reducing the conduction current of the temperature sensor can increase its sensitivity. The P-type GaN layer of the temperature sensor provided by this invention can act as a resistor after the Schottky barrier is turned on, equivalent to a series resistor. The larger the series resistance, the smaller the conduction current, the higher the sensitivity of the temperature sensor, and the lower the leakage current. In particular, the equivalent resistance of the semi-circular ring structure P-type GaN layer provided by this invention is larger than that of the normal rectangular structure, therefore the temperature sensor provided by this invention has higher sensitivity.

[0037] As can be seen from the above, the T-type anode GaN Schottky barrier diode provided by the present invention can adjust and expand the subthreshold region by combining the P-type GaN layer and the Schottky diode, thereby improving the measurement accuracy of the heterojunction temperature, while maintaining the advantages of high linearity, low on-state voltage and low reverse leakage current.

[0038] Furthermore, the T-anode GaN Schottky temperature sensor provided by this invention is a Schottky barrier diode with a lateral structure having a 2DEG channel. It can be fabricated on the same epitaxial wafer as HEMT devices based on the same structure. The temperature sensor has a simple structure and is consistent with the structure of HEMT devices. During integration, the temperature sensor can be well integrated with HEMT devices without additional processes, making high-density integration feasible for the T-anode GaN Schottky temperature sensor.

[0039] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of a T-type anode GaN Schottky temperature sensor provided in an embodiment of the present invention;

[0041] Figure 2 The example given is as follows Figure 1 The specific materials of each layer in the temperature sensor shown;

[0042] Figure 3 This is a flowchart illustrating a method for fabricating a T-type anode GaN Schottky temperature sensor according to an embodiment of the present invention.

[0043] Figures 4(a)-4(e) It is to utilize Figure 3 A schematic diagram of the sample structure during the fabrication of the T-type anode GaN Schottky temperature sensor using the method shown. Detailed Implementation

[0044] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0045] To address the aforementioned problems in the prior art, this invention provides a T-type anode GaN Schottky temperature sensor and its fabrication method.

[0046] First, the T-type anode GaN Schottky temperature sensor provided in the embodiments of the present invention will be described in detail. For example... Figure 1 As shown, the T-type anode GaN Schottky temperature sensor includes: a substrate, a nucleation layer, a buffer layer, a channel layer, an AlN insertion layer, a barrier layer, a semi-circular annular P-type GaN layer, a first passivation layer, a second passivation layer, a semi-cylindrical anode groove, an annular cathode groove, a T-type anode, and an annular cathode.

[0047] The substrate is made of silicon material with a P-type (1,1,1) crystal orientation; the nucleation layer, buffer layer, channel layer, AlN insertion layer, barrier layer, and semi-circular P-type GaN layer are made of AlN material, AlGaN material, GaN material, AlN material, AlGaN material, and Mg-doped material, respectively. + It is made of GaN material with ions.

[0048] A semi-circular P-type GaN layer is stacked on one side above the barrier layer, with its arc curving towards the center of the device.

[0049] The first passivation layer covers the area on the upper surface of the barrier layer except for the semi-circular P-type GaN layer; the first passivation layer and the semi-circular P-type GaN layer have the same thickness.

[0050] For example, the first passivation layer may be made of Si3N4 material.

[0051] The second passivation layer covers the upper surface of the semi-circular P-type GaN layer and the first passivation layer.

[0052] For example, the second passivation layer may be made of SiO2 material.

[0053] The semi-cylindrical anode groove is located inside the ring of the semi-circular P-type GaN layer; the depth of the semi-cylindrical anode groove is equal to the sum of the thicknesses of the second passivation layer and the semi-circular P-type GaN layer.

[0054] The annular cathode groove surrounds the semi-circular P-type GaN layer and is spaced a certain distance from the semi-circular P-type GaN layer. The depth of the annular cathode groove is greater than the sum of the thicknesses of the second passivation layer, the first passivation layer, and the barrier layer.

[0055] The T-shaped anode is formed by filling the semi-cylindrical anode groove with the anode Schottky contact metal and overlapping the second passivation layer around the semi-cylindrical anode groove.

[0056] For example, the anode Schottky metal may include Ti, Al, and Au.

[0057] The annular cathode is a cathode ohmic metal that fills the annular cathode groove and overlaps with the second passivation layer around the annular cathode groove.

[0058] For example, the cathode ohmic metal may include Ti, Al, Ni, and Au.

[0059] The T-type anode GaN Schottky temperature sensor provided in this embodiment of the invention has the following beneficial effects:

[0060] First, a semi-cylindrical anode electrode is used. The semi-circular electrode electric field generated by the semi-cylindrical anode electrode is not as concentrated as that of a rectangular electrode, which can reduce the problem of large boundary electric field peaks, thereby alleviating electric field spikes and protecting the Schottky contact of the anode. At the same time, the semi-cylindrical anode electrode can also reduce reverse leakage current and increase forward conduction current, so that the temperature sensor of the present invention requires a lower anode voltage and generates less power consumption under the same current.

[0061] Secondly, retaining the semi-circular P-type GaN layer not only depletes the two-dimensional electron gas beneath the P-type GaN layer, preventing the device from being constantly on, but also allows for better control of the temperature sensor's on / off state, thus avoiding interference with the normal operation of other devices in an integrated environment. Since the temperature sensor itself is a Schottky barrier diode, placing the P-type GaN layer under the anode electrode would affect the normal conduction of the Schottky diode. The temperature sensor provided in this embodiment of the invention forms the P-type GaN layer as a semi-circular ring attached to the semi-circular anode electrode, keeping the P-type GaN layer as far away as possible from the contact interface between the metal and the barrier layer, reducing the influence of the P-type GaN layer on the Schottky barrier, while simultaneously allowing the P-type GaN layer to serve as the equivalent series resistance of the temperature sensor.

[0062] Finally, applying a voltage to the T-shaped anode of the temperature sensor provided in this embodiment of the invention will result in the following three operating stages: 1. The Schottky barrier is not conducting, and electrons are about to cross the Schottky barrier; 2. The Schottky barrier is conducting, but the current is very small, and the P-type GaN layer is equivalent to a series resistor, playing a role in conductivity modulation; 3. The conductivity modulation effect of the P-type GaN layer is exhausted, the 2DEG is completely released, and full conduction occurs. As can be seen from the performance of temperature sensor devices, reducing the conduction current of the temperature sensor can increase its sensitivity. The P-type GaN layer of the temperature sensor provided in this embodiment of the invention can act as a resistor after the Schottky barrier is turned on, equivalent to a series resistor. The larger the series resistance, the smaller the conduction current, the higher the sensitivity of the temperature sensor, and the lower the leakage current. In particular, the equivalent resistance of the semi-circular ring structure P-type GaN layer provided in this embodiment of the invention is larger than that of the normal rectangular structure, therefore the temperature sensor provided in this embodiment of the invention has higher sensitivity.

[0063] As can be seen from the above, the T-type anode GaN Schottky barrier diode provided in this embodiment of the invention can adjust and expand the subthreshold region by combining the P-type GaN layer and the Schottky diode, thereby improving the measurement accuracy of the heterojunction temperature, while maintaining the advantages of high linearity, low on-state voltage and low reverse leakage current.

[0064] Furthermore, the T-type anode GaN Schottky temperature sensor provided in this embodiment of the invention is a Schottky barrier diode with a lateral structure having a 2DEG channel. It can be fabricated on the same epitaxial wafer as HEMT devices based on the same structure. The temperature sensor has a simple structure and is consistent with the structure of HEMT devices. During integration, the temperature sensor can be well integrated with HEMT devices without additional processes, making high-density integration feasible for the T-type anode GaN Schottky temperature sensor.

[0065] Optionally, in one embodiment, the T-type anode GaN Schottky temperature sensor provided by the present invention can also be doped with arsenic ions on the inner wall of the annular cathode groove. By heavily doping with arsenic ions, the on-resistance can be reduced and an ohmic contact can be formed. The reduction of on-resistance will not significantly change the equilibrium carrier concentration inside the semiconductor, which can make the temperature sensor work more stably and improve the robustness of the temperature sensor.

[0066] Optionally, in one embodiment, the T-type anode GaN Schottky temperature sensor provided by this invention introduces hydrogen ions into a semi-circular p-type GaN layer. The introduced hydrogen ions can passivate the Mg doped in the semi-circular p-type GaN layer. + Ions are used to passivate the defect states in the semi-circular P-type GaN layer, thereby obtaining a temperature sensor with high stability, which ensures that the conductivity of the temperature sensor remains stable even under high pressure and high temperature operating conditions.

[0067] The embodiments of the present invention do not limit the thickness of each structural layer of the T-anode GaN Schottky temperature sensor, and can select it according to the actual performance requirements of the T-anode GaN Schottky temperature sensor.

[0068] Based on the same inventive concept, this invention also provides a method for fabricating a T-type anode GaN Schottky temperature sensor. The method for fabricating a T-type anode GaN Schottky temperature sensor provided by this invention will be described in detail below.

[0069] See Figure 3 As shown in the figure, the method for fabricating a T-type anode GaN Schottky temperature sensor provided by an embodiment of the present invention includes the following steps:

[0070] Step 1: Fabrication of an epitaxial wafer; The epitaxial wafer, from bottom to top, includes a substrate, a nucleation layer, a buffer layer, a channel layer, an AlN insertion layer, a barrier layer, and a P-type GaN layer.

[0071] The materials used in each layer of the epitaxial wafer, such as Figure 2 As shown, the substrate, nucleation layer, buffer layer, channel layer, AlN insertion layer, barrier layer, and p-type GaN layer are made of Si, AlN, AlGaN, GaN, AlN, AlGaN, and doped Mg, respectively. + It is composed of GaN material.

[0072] Specifically, a low-temperature AlN nucleation layer is first epitaxially grown on the upper surface of a Si substrate using MOCVD (Metal-organic Chemical Vapor Deposition) technology, and then a high-temperature AlN nucleation layer is epitaxially grown on the upper surface of the low-temperature AlN nucleation layer; the thickness of the low-temperature AlN nucleation layer can be 30 nm, and the thickness of the high-temperature AlN nucleation layer can be 170 nm.

[0073] After the nucleation layer was prepared, undoped Al was deposited on the surface of the nucleation layer using MOCVD technology, with trimethylaluminum as the aluminum source, trimethylgallium as the gallium source, and ammonia as the ammonia source. 0.3 Ga 0.7 N buffer layer, the thickness of the buffer layer is 5μm.

[0074] After the buffer layer was prepared, an undoped GaN channel layer was deposited on the upper surface of the buffer layer using trimethylgallium as the gallium source and ammonia as the ammonia source, with a thickness of 200 nm.

[0075] After the channel layer was fabricated, undoped Al was deposited on the upper surface of the channel layer using MOCVD technology, with trimethylgallium as the gallium source, trimethylaluminum as the aluminum source, and ammonia as the ammonia source. 0.2 Ga 0.8 N-type barrier layer; the thickness of the barrier layer is 15 nm.

[0076] After the barrier layer was fabricated, a Mg+-doped GaN layer was epitaxially grown on the surface of the barrier layer using MOCVD technology. The epitaxially grown Mg+-doped GaN layer was then annealed at high temperature to form a p-type GaN layer; the thickness of the p-type GaN layer was 70 nm; and the doping concentration of Mg+ ions in the p-type GaN layer was 10. 19 cm -3 .

[0077] Optionally, before step two, the method may further include: depositing Si3N4 on the surface of the prepared P-type GaN layer for passivation; and removing the deposited Si3N4 layer on the surface of the P-type GaN layer using a hydrogen ion wet process to introduce hydrogen ions into the P-type GaN layer. For example, as shown in Figure 4(a), firstly, Si3N4 is deposited on the surface of the prepared P-type GaN layer to passivate and form a Si3N4 passivation layer. Next, photoresist is spin-coated onto the Si3N4 passivation layer and exposed and developed. The Si3N4 passivation layer is then removed using a BHF (Buffered Hydrofluoric Acid) solution. The BHF solution is prepared by mixing 6 volumes of ammonium fluoride (NH4F, 40% solution) and 1 volume of hydrofluoric acid (HF). Diluting it in water at a 7:1 ratio before use allows for better control of the etching rate. By removing the Si3N4 passivation layer using a wet process, defect states in the P-type GaN layer can be passivated.

[0078] Step 2: Define a semi-circular region on one side of the surface of the P-type GaN layer, and etch downwards into the region outside the semi-circular region, extending the etching depth to the barrier layer; wherein, the arc of the semi-circular region bends toward the center of the epitaxial wafer.

[0079] As shown in Figure 4(b), a semi-circular region is first defined on one side of the surface of the P-type GaN layer. Then, photoresist is spin-coated outside the defined semi-circular region and exposed and developed. The P-type GaN layer outside the semi-circular region is etched downwards using a BHF solution until the etching depth extends to the barrier layer.

[0080] Step 3: Deposit the first passivation layer on the surface of the current sample, with the same thickness as the P-type GaN layer.

[0081] As shown in Figure 4(c), on the barrier layer on the current sample surface, that is, the area where the P-type GaN layer has been etched away, a first passivation layer is deposited using PECVD technology with silane as the silicon source and ammonia as the ammonia source, so that the thickness of the passivation layer is the same as the thickness of the P-type GaN layer. Therefore, after the first passivation layer is deposited, its upper surface is flush with the P-type GaN layer. For example, the first passivation layer can be a Si3N4 passivation layer.

[0082] Step 4: Deposit a second passivation layer on the surface of the current sample.

[0083] As shown in Figure 4(c), a second passivation layer is deposited on the surface of the current sample, i.e., the surface of the P-type GaN layer and the first passivation layer. After the second passivation layer is deposited, both the P-type GaN layer and the first passivation layer are covered underneath. For example, the second passivation layer can be a SiO2 passivation layer.

[0084] Step 5: Define the anode region on the surface of the second passivation layer above the remaining P-type GaN layer, and etch the anode region downwards to the barrier layer to form a semi-cylindrical anode groove. The remaining P-type GaN layer is a semi-circular annular P-type GaN layer.

[0085] Step 6: Deposit Schottky metal in the semi-cylindrical anode groove and overlap the Schottky metal with the second passivation layer around the anode groove to form a T-type anode with Schottky contact.

[0086] Specifically, in a semi-cylindrical anode groove, Ti, Al and Au metals are sputtered from bottom to top using PVD (Physical Vapor Deposition) technology to prepare a Schottky contact T-type anode. The thicknesses of each metal layer are 20 nm, 250 nm and 30 nm, respectively. The sputtered T-type anode metal is then subjected to rapid thermal annealing, and the T-type anode preparation is completed.

[0087] Step 7: Define an annular cathode region around the semi-circular area on the surface of the second passivation layer, and etch the annular cathode region downwards to extend the etching depth into the channel layer to form an annular cathode groove.

[0088] As shown in Figure 4(d), the annular cathode region and the semi-circular region are separated by a certain distance.

[0089] Optionally, prior to step eight, the preparation method may further include: doping the inner wall of the annular cathode groove with arsenic ions to reduce the on-resistance and form an ohmic contact, wherein the doping concentration of arsenic ions is greater than 10. 20 cm -3 .

[0090] Step 8: Deposit ohmic metal in the annular cathode groove to form an annular cathode with ohmic contact, thus obtaining the prepared T-type anode GaN Schottky temperature sensor.

[0091] Specifically, an ohmic contact annular cathode is prepared by sputtering Ti, Al, Ni and Au metals from bottom to top in the annular cathode groove using PVD technology. The thicknesses of each metal layer are 20 nm, 140 nm, 50 nm and 40 nm, respectively. The sputtered annular cathode metal is then subjected to rapid thermal annealing to obtain the prepared T-type anode GaN Schottky temperature sensor as shown in Figure 4(e).

[0092] The T-type anode GaN Schottky temperature sensor prepared using the preparation method provided in this embodiment of the invention has the following beneficial effects:

[0093] First, a semi-cylindrical anode electrode is used. The semi-circular electrode electric field generated by the semi-cylindrical anode electrode is not as concentrated as that of a rectangular electrode, which can reduce the problem of large boundary electric field peaks, thereby alleviating electric field spikes and protecting the Schottky contact of the anode. At the same time, the semi-cylindrical anode electrode can also reduce reverse leakage current and increase forward conduction current. This makes the T-type anode GaN Schottky temperature sensor prepared by the preparation method provided in this embodiment of the invention require a lower anode voltage and generate less power consumption under the same current.

[0094] Secondly, retaining the semi-circular P-type GaN layer not only depletes the two-dimensional electron gas beneath the P-type GaN layer, preventing the device from being constantly on, but also allows for better control of the temperature sensor's on / off state, thus avoiding interference with the normal operation of other devices in an integrated environment. Since the temperature sensor itself is a Schottky barrier diode, placing the P-type GaN layer under the anode electrode would affect the normal conduction of the Schottky diode. The T-type anode GaN Schottky temperature sensor fabricated by the method provided in this embodiment of the invention forms the P-type GaN layer into a semi-circular ring that fits the semi-circular anode electrode, keeping the P-type GaN layer as far away as possible from the contact interface between the metal and the barrier layer, reducing the influence of the P-type GaN layer on the Schottky barrier, while simultaneously allowing the P-type GaN layer to serve as the equivalent series resistance of the temperature sensor.

[0095] Finally, applying a voltage to the T-shaped anode of the T-shaped anode GaN Schottky temperature sensor prepared by the method provided in this embodiment of the invention will result in the following three operating stages: 1. The Schottky barrier is not conducting, and electrons are about to cross it; 2. The Schottky barrier is conducting, but the current is very small, and the P-type GaN layer is equivalent to a series resistor, playing a role in conductivity modulation; 3. The conductivity modulation effect of the P-type GaN layer is exhausted, the 2DEG is completely released, and full conduction occurs. As can be seen from the performance of temperature sensor devices, reducing the conduction current of the temperature sensor can increase its sensitivity. In the T-shaped anode GaN Schottky temperature sensor prepared by the method provided in this embodiment of the invention, the P-type GaN layer can act as a resistor after the Schottky barrier is turned on, equivalent to a series resistor. The larger the series resistance, the smaller the conduction current, the higher the sensitivity of the temperature sensor, and the lower the leakage current. In particular, the equivalent resistance of the P-type GaN layer in the semi-circular annular structure of the T-type anode GaN Schottky temperature sensor prepared by the preparation method provided in the embodiments of the present invention is larger than that of the normal rectangular structure. Therefore, the T-type anode GaN Schottky temperature sensor prepared by the preparation method provided in the embodiments of the present invention has higher sensitivity.

[0096] As can be seen from the above, the T-type anode GaN Schottky temperature sensor prepared by the preparation method provided in this embodiment of the invention can adjust and expand the subthreshold region by combining the P-type GaN layer and the Schottky diode, thereby improving the measurement accuracy of the heterojunction temperature, while maintaining the advantages of high linearity, low on-state voltage and low reverse leakage current.

[0097] Furthermore, the T-type anode GaN Schottky temperature sensor prepared by the preparation method provided in this embodiment of the invention is a Schottky barrier diode with a lateral structure having a 2DEG channel. It can be prepared on the same epitaxial wafer as HEMT devices based on the same structure. The temperature sensor has a simple structure and is consistent with the structure of HEMT devices. During integration, the temperature sensor can be well integrated with HEMT devices without additional processes, making the T-type anode GaN Schottky temperature sensor feasible for high-density integration.

[0098] In practical applications, the above steps can be combined with the fabrication process of GaN-based HEMT devices. For example, the fabrication of the epitaxial wafer can be combined with the fabrication of the epitaxial wafer of the GaN-based HEMT device. The specific combination process is related to the specific structure of the HEMT device, and will not be elaborated in the embodiments of the present invention.

[0099] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A T-type anode GaN Schottky temperature sensor, characterized in that, include: The substrate, nucleation layer, buffer layer, channel layer, AlN insertion layer and barrier layer are stacked from bottom to top; A semi-circular P-type GaN layer is stacked on one side above the barrier layer, with its arc curving towards the center of the device. A first passivation layer covers the area on the upper surface of the barrier layer except for the semi-circular P-type GaN layer; the first passivation layer and the semi-circular P-type GaN layer have the same thickness. The second passivation layer covers the upper surface of the semi-circular annular P-type GaN layer and the first passivation layer; The semi-cylindrical anode groove is located inside the ring of the semi-circular P-type GaN layer; the depth of the semi-cylindrical anode groove is equal to the sum of the thicknesses of the second passivation layer and the semi-circular P-type GaN layer. An annular cathode groove surrounds the semi-circular annular P-type GaN layer and is spaced a certain distance from the semi-circular annular P-type GaN layer. The depth of the annular cathode groove is greater than the sum of the thicknesses of the second passivation layer, the first passivation layer, and the barrier layer. The T-shaped anode is a Schottky metal anode, which fills the semi-cylindrical anode groove and overlaps the second passivation layer around the semi-cylindrical anode groove; The annular cathode is a cathode ohmic metal that fills the annular cathode groove and overlaps the second passivation layer around the annular cathode groove.

2. The T-type anode GaN Schottky temperature sensor according to claim 1, characterized in that, The inner wall of the annular cathode groove is doped with arsenic ions.

3. The T-type anode GaN Schottky temperature sensor according to claim 1, characterized in that, Hydrogen ions are introduced into the semi-circular annular P-type GaN layer.

4. The T-type anode GaN Schottky temperature sensor according to claim 1, characterized in that, The first passivation layer includes a Si3N4 passivation layer.

5. The T-type anode GaN Schottky temperature sensor according to claim 1, characterized in that, The second passivation layer includes a SiO2 passivation layer.

6. The T-type anode GaN Schottky temperature sensor according to claim 1, characterized in that, The anode Schottky metal includes: Ti, Al and Au.

7. The T-type anode GaN Schottky temperature sensor according to claim 1, characterized in that, The cathode ohmic metal includes: Ti, Al, Ni and Au.

8. A method for fabricating a T-type anode GaN Schottky temperature sensor, characterized in that, include: Step 1: Fabrication of an epitaxial wafer; the epitaxial wafer comprises, from bottom to top, a substrate, a nucleation layer, a buffer layer, a channel layer, an AlN insertion layer, a barrier layer, and a P-type GaN layer; Step 2: Define a semi-circular region on one side of the surface of the P-type GaN layer, and etch downwards into the region outside the semi-circular region, extending the etching depth to the barrier layer; wherein, the arc of the semi-circular region bends toward the center of the epitaxial wafer. Step 3: Deposit the first passivation layer on the surface of the current sample, with the same thickness as the P-type GaN layer. Step 4: Deposit a second passivation layer on the surface of the current sample; Step 5: Define an anode region on the surface of the second passivation layer above the remaining P-type GaN layer, and etch the anode region downwards to the barrier layer to form a semi-cylindrical anode groove. The remaining P-type GaN layer is a semi-circular annular P-type GaN layer. Step 6: Deposit Schottky metal in the semi-cylindrical anode groove and overlap the Schottky metal with the second passivation layer around the anode groove to form a T-type anode with Schottky contact; Step 7: Define an annular cathode region around the semi-circular region on the surface of the second passivation layer, and etch the annular cathode region downwards to the depth of the etching extending into the channel layer to form an annular cathode groove; the annular cathode region is spaced a certain distance from the semi-circular region; Step 8: Deposit ohmic metal in the annular cathode groove to form an annular cathode with ohmic contact, thus obtaining the prepared T-type anode GaN Schottky temperature sensor.

9. The method for fabricating a T-type anode GaN Schottky temperature sensor according to claim 8, characterized in that, Prior to step eight, the method further includes: Arsenic ions are doped into the inner wall of the annular cathode groove.

10. The method for fabricating a T-type anode GaN Schottky temperature sensor according to claim 8, characterized in that, Before step two, the method further includes: Si3N4 was deposited on the surface of the prepared P-type GaN layer for passivation; The Si3N4 layer deposited on the surface of the P-type GaN layer is removed by a hydrogen ion wet process to introduce hydrogen ions into the P-type GaN layer.

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