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CN-122028501-A - Gallium nitride structure with high transient tolerance capability and application thereof in robot arm scram device

CN122028501ACN 122028501 ACN122028501 ACN 122028501ACN-122028501-A

Abstract

The invention relates to the technical field of gallium nitride semiconductors, and discloses a gallium nitride structure with high transient tolerance and application thereof in a robot arm emergency stop device, wherein the gallium nitride structure comprises a silicon carbide device formed by MOS cells and a gallium nitride device formed by a GaN structure, and the gallium nitride device is positioned on the back of the silicon carbide device; the MOS unit cell comprises a semiconductor epitaxial layer, an MOS source electrode, an MOS grid electrode and an MOS medium layer covering the surface of the MOS grid electrode, wherein the semiconductor epitaxial layer comprises an N substrate layer, an N drift layer, a P+ layer, an N well layer and a P well layer, electric field distribution is optimized, and transient voltage endurance capability is remarkably improved. By arranging the lightly doped N layer in the middle of the N drift layer, arranging the laterally symmetrical special-shaped P-layers with the opposite sides in the shape of circular arc waves on two sides, and matching with the circular arc wave surface structural design of the concave P-layers and the lightly doped concave N layer, the device can accurately disperse the local electric field concentration area inside the device, guide the electric field to be uniformly distributed, and effectively offset counter electromotive force and voltage peak generated during the sudden stop of the mechanical arm.

Inventors

  • XU YILI
  • REN NA
  • LI JIASHUAI
  • DING JINCHAO
  • YANG QI
  • LI XIN

Assignees

  • 杭州谱析光晶半导体科技有限公司

Dates

Publication Date
20260512
Application Date
20260414

Claims (9)

  1. 1. A gallium nitride structure with high transient tolerance, comprising a silicon carbide device composed of MOS cells (1), and a gallium nitride device composed of a GaN structure (2), wherein the gallium nitride device is positioned on the back surface of the silicon carbide device; the MOS unit cell (1) comprises a semiconductor epitaxial layer, a MOS source electrode (101), a MOS gate electrode (102) and a MOS dielectric layer (103) covering the surface of the MOS gate electrode (102); the semiconductor epitaxial layer comprises an N substrate layer (107), an N drift layer (104), a P+ layer (105), an N well layer (106) and a P well layer (108), and is characterized in that a lightly doped N layer (109) is arranged in the middle of the N drift layer (104) of the MOS cell; The MOS cell (1) is internally provided with side symmetrical special-shaped P-layers (111) at the left side and the right side of an N drift layer (104), and the profiles of the opposite side sections of the side symmetrical special-shaped P-layers (111) at the two sides are in arc wavy shapes, wherein the top ends of the side symmetrical special-shaped P-layers (111) are contacted with an N substrate layer (107), and the bottom ends of the side symmetrical special-shaped P-layers (111) at the two sides are in opposite horizontal shapes; The GaN structure (2) sequentially comprises a buffer layer (201), a GaN channel layer (202), an AlGaN barrier layer (204), a covering dielectric layer (207) and a GaN grid electrode (205) from bottom to top; a GaN source electrode (206) is deposited on the right side of the GaN structure (2); A GaN drain (203) is deposited on the GaN structure (2) on a side away from the GaN source (206).
  2. 2. The GaN structure with high transient withstand capability of claim 1, wherein the top of the inside of the lightly doped N layer (109) is formed with a heavily doped N layer (110) by ion implantation, the top of the heavily doped N layer (110) is in contact with the N substrate layer (107), the middle part of the bottom of the cross-section outline of the heavily doped N layer (110) is in a horizontal shape, and the two sides of the top are in arc wavy shapes.
  3. 3. The GaN structure with high transient withstand capability of claim 2, wherein the inner two side regions of the heavily doped N layer (110) are formed with concave P-layers (112) by ion implantation, the top ends of the concave P-layers (112) are contacted with the N substrate layer (107), and the bottoms of the cross-section outlines of the concave P-layers (112) are arc wavy surfaces.
  4. 4. A GaN structure with high transient withstand capability according to claim 3, wherein a lightly doped concave N layer (113) is formed between two concave P-layers (112) by ion implantation, the top of the lightly doped concave N layer (113) is in a relative inclined shape, and the bottom of the cross section outline of the lightly doped concave N layer (113) is in a circular arc wavy surface.
  5. 5. The GaN structure with high transient withstand capability of claim 4, wherein a convex P-layer (114) is formed inside the lightly doped N layer (109) through ion implantation, the bottom end of the convex P-layer (114) is in contact with the upper surface of the grid electrode (102), and the top of the cross-section outline of the convex P-layer (114) is an arc wavy surface.
  6. 6. The gallium nitride structure with high transient withstand capability of claim 5, wherein a top of said convex P-layer (114) is complementary to a bottom of said lightly doped concave N-layer (113).
  7. 7. The GaN structure with high transient withstand capability of claim 1, wherein a bottom edge of said GaN source (206) is in ohmic contact with the N substrate layer (107), and a side edge of said GaN source (206) is in ohmic contact with the GaN channel layer (202) and the AlGaN barrier layer (204).
  8. 8. The gallium nitride structure with high transient withstand capability of claim 1, wherein the GaN gate (205) is located near the GaN source (206).
  9. 9. Use of a gallium nitride structure with high transient withstand capability in a robot scram device, characterized in that it is applied to a gallium nitride structure with high transient withstand capability according to any one of claims 1-8, comprising the steps of: s1, integrating the gallium nitride structure with high transient tolerance capability into a power control module of a robot arm emergency stop device, enabling the GaN drain electrode (203) to be electrically connected with a power supply output end of the robot arm, enabling the MOS source electrode (101) to be electrically connected with a grounding end of a power loop of the robot arm, and enabling the MOS grid electrode (102) and the GaN grid electrode (205) to be respectively connected with a signal output end of the robot arm emergency stop control unit; S2, when the robot arm normally operates, the scram control unit inputs a driving voltage to the MOS grid electrode (102) to enable the MOS unit cell (1) to be conducted, and simultaneously inputs a matching voltage to the GaN grid electrode (205) to enable the GaN structure (2) to be opened, and a conducting loop is formed by the current flowing through the GaN drain electrode (203), the GaN structure (2), the N substrate layer (107), the MOS unit cell (1) and the MOS source electrode (101) to supply power for a power system of the robot arm; S3, when a robot arm triggers an emergency stop instruction, the emergency stop control unit immediately cuts off driving voltages to the MOS grid electrode (102) and the GaN grid electrode (205), the laterally symmetrical special-shaped P-layer (111) in the MOS unit cell (1) is matched with the lightly doped N layer (109) to disperse an electric field, structures such as the heavily doped N layer (110) and the concave P-layer (112) inhibit electric field concentration and parasitic effect, so that the MOS unit cell (1) is rapidly turned off, and meanwhile, the GaN structure (2) is rapidly turned off by depending on the characteristics of the AlGaN barrier layer (204) and the GaN channel layer (202), and a power loop of the robot arm is cut off; S4, in the emergency stop process, counter electromotive force and voltage peaks generated by high-load emergency stop of the mechanical arm are counteracted through each doped layer structure in the MOS unit cell (1) by utilizing the high transient tolerance characteristic of the gallium nitride structure, the serial voltage withstand structure formed by the GaN structure (2) and the silicon carbide device bears transient high-voltage impact, the safe emergency stop of the mechanical arm is completed, and the blocking state of the gallium nitride structure is maintained after the emergency stop until an emergency stop instruction is released, and a driving signal is input again.

Description

Gallium nitride structure with high transient tolerance capability and application thereof in robot arm scram device Technical Field The invention relates to the technical field of gallium nitride semiconductors, in particular to a gallium nitride structure with high transient tolerance capability and application thereof in a robot arm emergency stop device. Background The wide application of the industrial robot arm puts a severe requirement on the safety and reliability of the emergency stop device, a large counter electromotive force and voltage peak can be generated in an emergency stop instant power loop, and the core power switch device is required to have the performances of high transient voltage resistance, fast switch response and low conduction loss. The conventional silicon-based MOSFET and single silicon carbide or gallium nitride device of the conventional mechanical arm scram device have technical bottlenecks that the silicon-based MOSFET has low critical breakdown electric field and slow switching response, the single silicon carbide MOSFET has low carrier mobility and insufficient electric field distribution optimization, the single gallium nitride HEMT has transverse withstand voltage which easily causes the increase of the area of the device, the reduction of the reliability and the problems of gate overvoltage and latch failure. Patent CN115832040A relates to a silicon carbide based gallium nitride device and a preparation method thereof. The silicon carbide-based gallium nitride device comprises a semiconductor substrate, a drift layer, a buffer layer, a channel layer and a barrier layer, wherein the drift layer, the buffer layer, the channel layer and the barrier layer are sequentially stacked on the front surface of the semiconductor substrate, a grid electrode is arranged on the barrier layer, a source electrode is arranged on the channel layer and on the first side of the barrier layer, and an intermediate metal layer is arranged on the drift layer and is in contact with the buffer layer, the channel layer and the second side of the barrier layer. The drain electrode is arranged on the back surface of the semiconductor substrate. According to the application, the drain electrode is arranged on the back surface of the semiconductor substrate, and the two-dimensional electron gas is connected with the drift layer through the intermediate metal layer, so that the source electrode is connected with the drain electrode through the two-dimensional electron gas, the intermediate metal layer, the drift layer and the semiconductor substrate in sequence, and the high-voltage resistance of the HEMT device is improved through the drift layer and the semiconductor substrate on the premise of still having the high-speed on-off characteristic of the HEMT device. However, key challenges still remain to be overcome, the existing integration scheme of silicon carbide and gallium nitride is mostly surface splicing, deep heterogeneous fusion is not realized, power density is low, electrical interconnection is complex, a traditional doping layer structure of silicon carbide MOS cells cannot accurately disperse a local electric field, electric field distortion problem is outstanding, meanwhile, a targeted charge balance design is lacking, parasitic effect is not effectively inhibited, switching loss is high, a device is easy to fail in a transient process, and the device is difficult to adapt to working condition requirements of high-load scram and frequent start-stop of a robot arm, so that the integration scheme becomes a key bottleneck for restricting performance upgrading of the scram device, and a gallium nitride structure with high transient tolerance capability and application of the gallium nitride structure in the scram device are provided. Disclosure of Invention The invention aims to solve the problems that the power switch device for the existing robot arm emergency stop device has insufficient transient withstand voltage, uneven electric field distribution, slow switch response and high conduction loss, each single silicon carbide/gallium nitride device has a performance short plate, the simple integration scheme of silicon carbide and gallium nitride does not realize deep heterogeneous fusion, the power density is low, the electrical interconnection is complex, the traditional MOS cell structure cannot accurately disperse the local electric field, the parasitic effect is obvious, the device is easy to lose efficacy under the transient stress impact of high-load emergency stop, and the high-load emergency stop and frequent start-stop condition requirements of the robot arm are difficult to adapt. To solve the above-mentioned technical problem, according to one aspect of the present invention, more specifically, a gallium nitride structure with high transient withstand capability, including a silicon carbide device composed of MOS cells, and a gallium nitride device composed of GaN structure,