N-surface enhanced GaN bidirectional power device and preparation method thereof

Abstract

The invention provides an N-surface enhanced GaN bidirectional power device and a preparation method thereof, the N-surface enhanced GaN bidirectional power device comprises a substrate, an AlN nucleating layer, a buffer layer, a C-doped AlGaN layer, an AlGaN barrier layer, a GaN channel layer and a passivation layer, gate metal is located in a gate region and is connected with the GaN channel layer, a first drain and a second drain are arranged at two sides of the gate region, and the first drain is connected with the second drain. The first drain electrode comprises first Schottky contact metal and first ohmic contact metal connected with the first Schottky contact metal, and the second drain electrode comprises second Schottky contact metal and second ohmic contact metal connected with the second Schottky contact metal; the first Schottky contact metal is connected with the AlGaN barrier layer to form first Schottky contact, the first ohmic contact metal is connected with the GaN channel layer to form first ohmic contact, the second Schottky contact metal is connected with the AlGaN barrier layer to form second Schottky contact, and the second ohmic contact metal is connected with the GaN channel layer to form second ohmic contact. Therefore, the anti-radiation capability of the device is improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to an N-face enhanced GaN bidirectional power device and a preparation method thereof. Background Art

[0002] The semiconductor industry has developed rapidly for decades under Moore's Law. Silicon, the first-generation semiconductor material, has always been the most widely used semiconductor material due to its many advantages, and the silicon process is also the most mature integration process. With the application of various high-power devices, the requirements for the withstand voltage, frequency and other performance of power electronic devices are getting higher and higher. Although traditional Si and GaAs devices can still be applicable by continuously improving the manufacturing process, the cost is extremely high, and the limitations of the physical properties of materials such as Si and GaAs themselves can no longer meet the requirements of certain application scenarios. The third-generation semiconductor material gallium nitride (GaN) has the advantages of strong radiation resistance, high breakdown electric field, high electron mobility, good thermal conductivity, etc., and can obtain semiconductor devices with large bandwidth, high gain, high frequency withstand voltage, and smaller size, becoming a research hotspot in the field of high-power power electronic devices today.

[0003] However, the design of existing GaN devices is unreasonable, resulting in the lack of strong radiation resistance of GaN devices, which in turn affects the performance of GaN devices. Summary of the invention

[0004] In view of this, the present application provides an N-face enhanced GaN bidirectional power device and a preparation method thereof to improve the radiation resistance of the device.

[0005] The present application provides an N-face enhanced GaN bidirectional power device, comprising a substrate, an AlN nucleation layer, a buffer layer, a C-doped AlGaN layer, an AlGaN barrier layer, a GaN channel layer and a passivation layer stacked in sequence from bottom to top, a gate metal is located in a gate region and connected to the GaN channel layer, a first drain and a second drain are arranged on both sides of the gate region, the first drain comprises a first Schottky contact metal and a first ohmic contact metal connected to the first Schottky contact metal, and the second drain comprises a second Schottky contact metal and a second ohmic contact metal connected to the second Schottky contact metal;

[0006] Among them, the first Schottky contact metal is connected to the AlGaN barrier layer to form a first Schottky contact, the first ohmic contact metal is connected to the GaN channel layer to form a first ohmic contact, the second Schottky contact metal is connected to the AlGaN barrier layer to form a second Schottky contact, and the second ohmic contact metal is connected to the GaN channel layer to form a second ohmic contact.

[0007] In some embodiments, the first drain and the second drain are symmetrically arranged with respect to the gate metal.

[0008] In some embodiments, an AlGaN layer is disposed between the gate metal and the GaN channel layer, and the AlGaN layer forms a third Schottky contact with the gate metal.

[0009] In some embodiments, the first ohmic contact metal is located on a side of the first Schottky contact metal close to the gate metal, and the second ohmic contact metal is located on a side of the second Schottky contact metal close to the gate metal.

[0010] In some embodiments, the first Schottky contact metal and the first ohmic contact metal are short-circuited outside the active region.

[0011] In some embodiments, the second Schottky contact metal and the second ohmic contact metal are short-circuited outside the active region.

[0012] In some embodiments, the first Schottky contact metal and the second Schottky contact metal are symmetrically arranged with respect to the gate metal, and the first ohmic contact metal and the second ohmic contact metal are symmetrically arranged with respect to the gate metal.

[0013] In some embodiments, the passivation layer has a first through hole, a second through hole, a third through hole and a fourth through hole, the first through hole and the fourth through hole penetrate the passivation layer and the GaN channel layer to expose the AlGaN barrier layer, the first Schottky contact metal is filled in the first through hole to connect with the AlGaN barrier layer, the second Schottky contact metal is filled in the fourth through hole to connect with the AlGaN barrier layer, the second through hole and the third through hole penetrate the passivation layer to expose the GaN channel layer, the first ohmic contact metal is filled in the second through hole to connect with the GaN channel layer, and the second ohmic contact metal is filled in the third through hole to connect with the GaN channel layer.

[0014] The present application provides a method for preparing an N-face enhanced GaN bidirectional power device, which is used to prepare the N-face enhanced GaN bidirectional power device as described above, comprising:

[0015] Depositing an AlN nucleation layer, a buffer layer, a C-doped AlGaN layer, an AlGaN barrier layer, a GaN channel layer and a gate layer on the substrate in sequence;

[0016] Etching the gate layer to form a gate metal in the gate region;

[0017] forming a passivation layer on the gate metal and the GaN channel layer;

[0018] forming a first drain electrode and a second drain electrode on both sides of the gate region on the passivation layer, wherein the first drain electrode comprises a first Schottky contact metal and a first ohmic contact metal connected to the first Schottky contact metal, and the second drain electrode comprises a second Schottky contact metal and a second ohmic contact metal connected to the second Schottky contact metal;

[0019] Among them, the first Schottky contact metal is connected to the AlGaN barrier layer to form a first Schottky contact, the first ohmic contact metal is connected to the GaN channel layer to form a first ohmic contact, the second Schottky contact metal is connected to the AlGaN barrier layer to form a second Schottky contact, and the second ohmic contact metal is connected to the GaN channel layer to form a second ohmic contact.

[0020] In some embodiments, after forming the GaN channel layer and before forming the gate layer, the method further includes:

[0021] An AlGaN layer located in a gate region is formed on the GaN channel layer.

[0022] The present application provides an N-face enhanced GaN bidirectional power device and a preparation method thereof, comprising a substrate, an AlN nucleation layer, a buffer layer, a C-doped AlGaN layer, an AlGaN barrier layer, a GaN channel layer and a passivation layer which are sequentially stacked from bottom to top, a gate metal is located in a gate region and connected to the GaN channel layer, a first drain electrode and a second drain electrode are arranged on both sides of the gate region, the first drain electrode comprises a first Schottky contact metal and a first ohmic contact metal connected to the first Schottky contact metal, and the second drain electrode comprises a second Schottky contact metal and a second ohmic contact metal connected to the second Schottky contact metal; the first Schottky contact metal is connected to the AlGaN barrier layer to form a first Schottky contact, the first ohmic contact metal is connected to the GaN channel layer to form a first ohmic contact, the second Schottky contact metal is connected to the AlGaN barrier layer to form a second Schottky contact, and the second ohmic contact metal is connected to the GaN channel layer to form a second ohmic contact, so as to improve the radiation resistance of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 is a schematic diagram of the cross-sectional structure of a GaN bidirectional power device provided by the present application;

[0025] Figure 2 It is a schematic flow chart of the method for preparing a GaN bidirectional power device provided in the present application.

[0026] Reference numerals:

[0027] 10. Power device; 100. Substrate; 200. AlN nucleation layer; 300. Buffer layer; 400. C-doped AlGaN layer; 500. AlGaN barrier layer; 600. GaN channel layer; 700. Passivation layer; 800. Gate metal; 900. First drain; 910. First Schottky contact metal; 920. First ohmic contact metal; 1000. Second drain; 1010. Second Schottky contact metal; 1020. Second ohmic contact metal; 1100. AlGaN layer. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application are clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application. In the absence of conflict, the following embodiments and their technical features can be combined with each other.

[0029] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In the description of the present application, the meaning of "several" is at least one, such as one, two, etc., unless otherwise clearly and specifically defined.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by a person skilled in the art to which this application belongs. The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more related listed items. The terms "connection", "electrical connection", and "electrical connection" used herein include any direct and indirect electrical or structural connection means. Therefore, if the text describes a first device coupled / connected / electrically connected to a second device, it means that the first device can be directly electrically / structurally connected to the second device, or indirectly electrically / structurally connected to the second device through other devices or connection means.

[0031] The present application provides an N-face enhanced GaN bidirectional power device and a preparation method thereof, comprising a substrate, an AlN nucleation layer, a buffer layer, a C-doped AlGaN layer, an AlGaN barrier layer, a GaN channel layer and a passivation layer stacked in sequence from bottom to top, a gate metal is located in a gate region and connected to the GaN channel layer, a first drain and a second drain are arranged on both sides of the gate region, the first drain comprises a first Schottky contact metal and a first ohmic contact metal connected to the first Schottky contact metal, the second drain comprises a second Schottky contact metal and a second ohmic contact metal connected to the second Schottky contact metal; the first Schottky contact metal is connected to the AlGaN barrier layer to form a first Schottky contact, the first ohmic contact metal is connected to the GaN channel layer to form a first ohmic contact, the second Schottky contact metal is connected to the AlGaN barrier layer to form a second Schottky contact, and the second ohmic contact metal is connected to the GaN channel layer to form a second ohmic contact.

[0032] In the present application, a first drain and a second drain are respectively arranged on both sides of the gate metal, and the first drain and the second drain both include a Schottky contact and an ohmic contact, so that when the device is irradiated, the holes generated by the irradiation are collected by the first Schottky contact metal or the second Schottky contact metal through drift motion and diffusion motion, preventing the holes from accumulating in the channel, thereby improving the radiation resistance of the device, and at the same time, avoiding the local electric field strength of the device from being too high due to the accumulation of holes, thereby avoiding the decrease in the breakdown voltage of the device.

[0033] See also Figure 1 , Figure 1 The cross-sectional structure diagram of the GaN bidirectional power device provided by the present application. The present application provides an N-face enhanced GaN bidirectional power device 10, comprising a substrate 100, an AlN nucleation layer 200, a buffer layer 300, a C-doped AlGaN layer 400, an AlGaN barrier layer 500, a GaN channel layer 600 and a passivation layer 700 stacked in sequence from bottom to top, a gate metal 800 located in the gate region and connected to the GaN channel layer 600, a first drain 900 and a second drain 1000 disposed on both sides of the gate region, the first drain 900 comprising a first Schottky contact metal 910 and a first ohmic contact connected to the first Schottky contact metal 910 Metal 920, the second drain 1000 includes a second Schottky contact metal 1010 and a second ohmic contact metal 1020 connected to the second Schottky contact metal 1010; wherein the first Schottky contact metal 910 is connected to the AlGaN barrier layer 500 to form a first Schottky contact, the first ohmic contact metal 920 is connected to the GaN channel layer 600 to form a first ohmic contact, the second Schottky contact metal 1010 is connected to the AlGaN barrier layer 500 to form a second Schottky contact, and the second ohmic contact metal 1020 is connected to the GaN channel layer 600 to form a second ohmic contact.

[0034] In the present application, a first drain 900 and a second drain 1000 are respectively arranged on both sides of the gate metal 800, and the first drain 900 and the second drain 1000 both include a Schottky contact and an ohmic contact, so that when the device is irradiated, the holes generated by the irradiation are collected by the first Schottky contact metal 910 or the second Schottky contact metal 1010 through drift motion and diffusion motion, thereby preventing the holes from accumulating in the channel, thereby improving the radiation resistance of the device, and at the same time, avoiding the local electric field strength of the device from being too high due to the accumulation of holes, thereby avoiding the decrease in the breakdown voltage of the device.

[0035] In the present application, the first drain 900 and the second drain 1000 are respectively arranged on both sides of the gate metal 800, and the first drain 900 and the second drain 1000 both include a Schottky contact and an ohmic contact, so that the device can be bidirectionally conductive, that is, when the device is working normally, if a high voltage is applied to the first drain 900 and a low voltage is applied to the second drain 1000, the electrons in the GaN channel layer 600 move from right to left, and the current flows from the first ohmic contact metal 920 to the second ohmic contact metal 920. Contact metal 1020, at this time, the first drain 900 can be used as a drain, and the second drain 1000 can be used as a source; if high voltage is applied to the second drain 1000 and low voltage is applied to the first drain 900, the electrons in the GaN channel layer 600 move from left to right, and the current flows from the second ohmic contact metal 1020 to the first ohmic contact metal 920. At this time, the second drain 1000 can be used as a drain, and the first drain 900 can be used as a source, thereby realizing bidirectional conduction of the device.

[0036] In the present application, when the N-face enhancement-type GaN bidirectional power device 10 provided in the present application is applied to a circuit, such as a BMS protection (battery protection) circuit, only one N-face enhancement-type GaN bidirectional power device 10 is required to achieve forward conduction and reverse conduction without the need to use two Si MOSFETs. Moreover, the use of the N-face enhancement-type GaN bidirectional power device 10 of the present application only requires one driving or control circuit, thereby simplifying the circuit design and reducing the device cost.

[0037] In the present application, the GaN channel layer 600 is arranged above the AlGaN barrier layer 500, that is, the heterojunction of the device of the present application is GaN / AlGaN, that is, the device of the present application is an N-face device, so that when making the first ohmic contact and the second ohmic contact, etching of the AlGaN barrier layer 500 can be avoided, thereby achieving lower ohmic contact resistance, and because the GaN channel layer 600 is arranged above the AlGaN barrier layer 500, the GaN channel layer 600 is closer to the gate metal 800, thereby achieving higher gate transconductance.

[0038] In one embodiment, the first drain 900 and the second drain 1000 are symmetrically arranged with respect to the gate metal 800, that is, the distance between the first drain 900 and the gate metal 800 is equal to the distance between the second drain 1000 and the gate metal 800. In the present application, by arranging the first drain 900 and the second drain 1000 to be symmetrically arranged with respect to the gate metal 800, the accumulation of holes in the channel is further prevented, thereby further improving the radiation resistance of the device and preventing the breakdown voltage of the device from decreasing, and at the same time, further improving the bidirectional conduction performance of the device.

[0039] In one embodiment, an AlGaN layer 1100 is disposed between the gate metal 800 and the GaN channel layer 600 , and the AlGaN layer 1100 forms a third Schottky contact with the gate metal 800 . In the present application, an AlGaN layer 1100 is arranged between the gate metal 800 and the GaN channel layer 600, that is, the device of the present application is an enhanced device, so that the piezoelectric polarization effect of the AlGaN barrier layer 500 on the GaN channel layer 600 can be offset by the AlGaN layer 1100, so that when the gate voltage is 0V, there is no high concentration of two-dimensional electron gas (2DEG) in the GaN channel layer 600 below the gate metal 800, thereby ensuring the performance of the device. At the same time, because the AlGaN layer 1100 is connected to the gate metal 800 to form a third Schottky contact, when the device is irradiated, the holes generated by the irradiation are collected by the first Schottky contact metal 910, the second Schottky contact metal 1010 or the third Schottky contact through drift motion and diffusion motion, preventing the holes from accumulating in the channel, thereby further improving the radiation resistance of the device, and at the same time, avoiding the excessive local electric field strength of the device due to the accumulation of holes, thereby improving the breakdown voltage of the device.

[0040] In one embodiment, the first ohmic contact metal 920 is located on a side of the first Schottky contact metal 910 close to the gate metal 800, and the second ohmic contact metal 1020 is located on a side of the second Schottky contact metal 1010 close to the gate metal 800. In the present application, by arranging the first Schottky contact metal 910 and the second Schottky contact metal on the outside of the first ohmic contact metal 920 and the second ohmic contact metal 1020, respectively, the device can achieve bidirectional conduction at the same time without affecting the normal operation of the device.

[0041] In one embodiment, the first Schottky contact metal 910 and the first ohmic contact metal 920 are short-circuited outside the active region so that current can flow smoothly from the drain region and the device can still work stably at high density, thereby improving the current output capacity of the device.

[0042] In one embodiment, the second Schottky contact metal 1010 and the second ohmic contact metal 1020 are short-circuited outside the active region so that the current can flow smoothly from the drain region and the device can still work stably at high density, thereby improving the current output capacity of the device.

[0043] In one embodiment, the first Schottky contact metal 910 and the second Schottky contact metal 1010 are symmetrically arranged with respect to the gate metal 800, and the first ohmic contact metal 920 and the second ohmic contact metal 1020 are symmetrically arranged with respect to the gate metal 800, that is, the distance between the first Schottky contact metal 910 and the gate metal 800 is equal to the distance between the second Schottky contact metal 1010 and the gate metal 800, and the distance between the first ohmic contact metal 920 and the gate metal 800 is equal to the distance between the second ohmic contact metal 1020 and the gate metal 800, so as to further prevent the accumulation of holes in the channel, thereby further improving the radiation resistance of the device and avoiding the decrease of the breakdown voltage of the device, and at the same time, further improving the bidirectional conduction performance of the device.

[0044] In one embodiment, the passivation layer 700 has a first through hole, a second through hole, a third through hole, and a fourth through hole. The first through hole and the fourth through hole penetrate the passivation layer 700 and the GaN channel layer 600 to expose the AlGaN barrier layer 500. The first Schottky contact metal 910 is filled in the first through hole to connect with the AlGaN barrier layer 500. The second Schottky contact metal 1010 is filled in the fourth through hole to connect with the AlGaN barrier layer 500. The second through hole and the third through hole penetrate the passivation layer 700 to expose the GaN channel layer 600. The first ohmic contact metal 920 is filled in the second through hole to connect with the GaN channel layer 600, and the second ohmic contact metal 1020 is filled in the third through hole to connect with the GaN channel layer 600, so that the first Schottky contact metal 910 and the second Schottky contact metal 1010 can be better connected to the AlGaN barrier layer 500 and the first ohmic contact metal 920 and the second ohmic contact metal 1020 can be better connected to the GaN channel layer 600, thereby improving the performance of the device.

[0045] See also Figure 2 , Figure 2 : is a schematic diagram of a process for preparing a GaN bidirectional power device provided by the present application. The present application also provides a method for preparing an N-face enhanced GaN bidirectional power device 10, which is used to prepare the N-face enhanced GaN bidirectional power device 10 provided by the present application, comprising:

[0046] S11, depositing an AlN nucleation layer, a buffer layer, a C-doped AlGaN layer, an AlGaN barrier layer, a GaN channel layer and a gate layer on the substrate in sequence.

[0047] S12, etching the gate layer to form a gate metal in the gate region.

[0048] S13, forming a passivation layer on the gate metal and the GaN channel layer.

[0049] Specifically, a passivation material layer is formed on the gate metal 800 and the GaN channel layer 600, and the passivation material layer is etched to form a passivation layer 700, wherein the passivation layer 700 has a second through hole, a third through hole and a gate through hole, and the second through hole, the third through hole and the gate through hole penetrate the passivation layer 700 to expose the GaN channel layer 600, wherein the gate through hole exposes the gate metal 800, and the second through hole and the third through hole are respectively located on both sides of the gate through hole.

[0050] S14, forming a first drain electrode and a second drain electrode on both sides of the gate region on the passivation layer, wherein the first drain electrode includes a first Schottky contact metal and a first ohmic contact metal connected to the first Schottky contact metal, and the second drain electrode includes a second Schottky contact metal and a second ohmic contact metal connected to the second Schottky contact metal;

[0051] Among them, the first Schottky contact metal is connected to the AlGaN barrier layer to form a first Schottky contact, the first ohmic contact metal is connected to the GaN channel layer to form a first ohmic contact, the second Schottky contact metal is connected to the AlGaN barrier layer to form a second Schottky contact, and the second ohmic contact metal is connected to the GaN channel layer to form a second ohmic contact.

[0052] Specifically, an ohmic contact metal is deposited on the passivation layer 700 and the gate metal 800; then, the ohmic contact metal is etched to form a first ohmic contact metal 920 filled in the second through hole to connect with the GaN channel layer 600 and a second ohmic contact metal 1020 filled in the third through hole to connect with the GaN channel layer 600; then, the first ohmic contact metal 920 and the second ohmic contact metal 1020 are rapidly annealed to form an ohmic contact; then, the passivation layer 700 is etched to form a first through hole and a fourth through hole, the first through hole and the fourth through hole penetrate the passivation layer 700 and the GaN channel layer 600 to expose the AlGaN barrier layer 500, and the first through hole and the fourth through hole are respectively located on both sides of the gate through hole; then, a Schottky contact metal is deposited on the passivation layer 700 and etched to form a Schottky contact metal filled in the first through hole to connect with the AlGaN barrier layer 500. The first Schottky contact metal 910 connected to the barrier layer 500 is filled in the fourth through hole to connect to the second Schottky contact metal 1010 of the AlGaN barrier layer 500; then, an insulating first dielectric layer is grown, and holes are etched to the first Schottky contact metal 910, the second Schottky contact metal 1010, the gate metal 800, the first ohmic contact metal 920 and the first dielectric layer at the second ohmic contact metal 1020, and a connecting metal is filled in the etched opening to form a first metal through hole, and the first connecting metal is deposited and etched. After etching, the first connecting metal interconnects the first Schottky contact metal 910 and the first ohmic contact metal 920 outside the active area, the first connecting metal interconnects the second Schottky contact metal 1010 and the second ohmic contact metal 1020 outside the active area, and the first connecting metal interconnects the gate metals 800 of other cells of the device.

[0053] In one embodiment, after forming the GaN channel layer 600 and before forming the gate layer, the method further includes:

[0054] An AlGaN layer 1100 located in the gate region is formed on the GaN channel layer 600 .

[0055] The above device is prepared by the preparation method provided by the present application, which simplifies the preparation method of the device and improves the efficiency of preparing the device. At the same time, the device prepared by the above method has a first drain 900 and a second drain 1000 respectively disposed on both sides of the gate metal 800, and the first drain 900 and the second drain 1000 both include a Schottky contact and an ohmic contact, so that when the device is irradiated, the holes generated by the irradiation are collected by the first Schottky contact metal 910 or the second Schottky contact metal 1010 through drift motion and diffusion motion, thereby preventing the holes from accumulating in the channel, thereby improving the radiation resistance of the device, and at the same time The local electric field strength of the device is too high due to the avoidance of hole accumulation, thereby avoiding the decrease of the breakdown voltage of the device; in addition, since the first drain 900 and the second drain 1000 are respectively arranged on both sides of the gate metal 800, and the first drain 900 and the second drain 1000 both include a Schottky contact and an ohmic contact, the device can be bidirectionally conductive; in addition, when the N-face enhanced GaN bidirectional power device 10 provided in the present application is applied to a circuit, such as a BMS protection (battery protection) circuit, only one N-face enhanced GaN bidirectional power device 10 is required to achieve forward conduction and reverse conduction, without using two Si MOSFET, and the N-face enhancement-type GaN bidirectional power device 10 of the present application only requires one driving or control circuit, thereby simplifying the circuit design and reducing the device cost at the same time; in addition, the GaN channel layer 600 is arranged above the AlGaN barrier layer 500, that is, the heterojunction of the device of the present application is GaN / AlGaN, so that when making the first ohmic contact and the second ohmic contact, etching of the AlGaN barrier layer 500 can be avoided, thereby achieving lower ohmic contact resistance, and because the GaN channel layer 600 is arranged above the AlGaN barrier layer 500, the GaN channel layer 600 is closer to the gate metal 800, thereby achieving higher gate transconductance.

[0056] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structural or equivalent process transformations made using the contents of the specification and drawings of the present application, such as the mutual combination of technical features between the embodiments, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. An N-face enhancement-mode GaN bidirectional power device, characterized in that: The invention comprises a substrate, an AlN nucleation layer, a buffer layer, a C-doped AlGaN layer, an AlGaN barrier layer, a GaN channel layer and a passivation layer which are sequentially stacked from bottom to top, a gate metal is located in a gate region and connected to the GaN channel layer, a first drain electrode and a second drain electrode are arranged on both sides of the gate region, the first drain electrode comprises a first Schottky contact metal and a first ohmic contact metal connected to the first Schottky contact metal, and the second drain electrode comprises a second Schottky contact metal and a second ohmic contact metal connected to the second Schottky contact metal; Among them, the first Schottky contact metal is connected to the AlGaN barrier layer to form a first Schottky contact, the first ohmic contact metal is connected to the GaN channel layer to form a first ohmic contact, the second Schottky contact metal is connected to the AlGaN barrier layer to form a second Schottky contact, and the second ohmic contact metal is connected to the GaN channel layer to form a second ohmic contact.

2. The N-face enhanced GaN bidirectional power device according to claim 1, characterized in that: The first drain and the second drain are symmetrically arranged with respect to the gate metal.

3. The N-face enhanced GaN bidirectional power device according to claim 1, characterized in that: An AlGaN layer is disposed between the gate metal and the GaN channel layer, and the AlGaN layer and the gate metal form a third Schottky contact.

4. The N-face enhanced GaN bidirectional power device according to claim 1, characterized in that: The first ohmic contact metal is located on a side of the first Schottky contact metal close to the gate metal, and the second ohmic contact metal is located on a side of the second Schottky contact metal close to the gate metal.

5. The N-face enhancement mode GaN bidirectional power device according to claim 1, characterized in that: The first Schottky contact metal and the first ohmic contact metal are short-circuited outside the active region.

6. The N-face enhanced GaN bidirectional power device according to claim 1, characterized in that: The second Schottky contact metal and the second ohmic contact metal are short-circuited outside the active region.

7. The N-face enhancement mode GaN bidirectional power device according to claim 2, characterized in that: The first Schottky contact metal and the second Schottky contact metal are symmetrically arranged with respect to the gate metal, and the first ohmic contact metal and the second ohmic contact metal are symmetrically arranged with respect to the gate metal.

8. The N-face enhancement mode GaN bidirectional power device according to claim 1, characterized in that: The passivation layer has a first through hole, a second through hole, a third through hole and a fourth through hole, the first through hole and the fourth through hole penetrate the passivation layer and the GaN channel layer to expose the AlGaN barrier layer, the first Schottky contact metal is filled in the first through hole to connect with the AlGaN barrier layer, the second Schottky contact metal is filled in the fourth through hole to connect with the AlGaN barrier layer, the second through hole and the third through hole penetrate the passivation layer to expose the GaN channel layer, the first ohmic contact metal is filled in the second through hole to connect with the GaN channel layer, and the second ohmic contact metal is filled in the third through hole to connect with the GaN channel layer.

9. A method for preparing an N-face enhanced GaN bidirectional power device, characterized in that: For preparing the N-face enhanced GaN bidirectional power device according to any one of claims 1 to 8, comprising: Depositing an AlN nucleation layer, a buffer layer, a C-doped AlGaN layer, an AlGaN barrier layer, a GaN channel layer and a gate layer on the substrate in sequence; Etching the gate layer to form a gate metal in the gate region; forming a passivation layer on the gate metal and the GaN channel layer; forming a first drain electrode and a second drain electrode on both sides of the gate region on the passivation layer, wherein the first drain electrode comprises a first Schottky contact metal and a first ohmic contact metal connected to the first Schottky contact metal, and the second drain electrode comprises a second Schottky contact metal and a second ohmic contact metal connected to the second Schottky contact metal; Among them, the first Schottky contact metal is connected to the AlGaN barrier layer to form a first Schottky contact, the first ohmic contact metal is connected to the GaN channel layer to form a first ohmic contact, the second Schottky contact metal is connected to the AlGaN barrier layer to form a second Schottky contact, and the second ohmic contact metal is connected to the GaN channel layer to form a second ohmic contact.

10. The method for preparing an N-face enhanced GaN bidirectional power device according to claim 9, characterized in that: After forming the GaN channel layer and before forming the gate layer, the method further includes: An AlGaN layer located in a gate region is formed on the GaN channel layer.

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