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CN-119181633-B - Method for improving electrical property of silicon carbide-metal composite interface

CN119181633BCN 119181633 BCN119181633 BCN 119181633BCN-119181633-B

Abstract

The invention relates to a method for improving electrical properties of a silicon carbide-metal composite interface, which comprises the specific steps of 1) cleaning and drying a monocrystalline silicon carbide substrate to obtain a clean monocrystalline silicon carbide substrate, 2) placing the clean monocrystalline silicon carbide substrate obtained in the step 1) on a laser galvanometer processing platform, carrying out annealing treatment on the surface of the monocrystalline silicon carbide substrate by using a femtosecond laser, and preparing a metal layer on the surface of the monocrystalline silicon carbide substrate according to requirements after the annealing treatment is finished. The method provided by the invention can effectively improve the electrical property of the silicon carbide-metal composite interface, and the carrier concentration and the conductivity of the obtained sample are both improved to a great extent.

Inventors

  • WANG XUEWEN
  • LIU GUOLONG
  • REN YUQI

Assignees

  • 武汉理工大学

Dates

Publication Date
20260512
Application Date
20240719

Claims (6)

  1. 1. A method for improving electrical properties of a silicon carbide-metal composite interface is characterized by comprising the following specific steps: 1) Cleaning and drying the monocrystalline silicon carbide substrate to obtain a clean monocrystalline silicon carbide substrate; 2) Placing the clean monocrystalline silicon carbide substrate obtained in the step 1) on a laser galvanometer processing platform, carrying out annealing treatment on the surface of the monocrystalline silicon carbide substrate by using a femtosecond laser, and preparing a metal layer on the surface of the monocrystalline silicon carbide substrate according to requirements after the annealing treatment is finished, wherein the technological conditions of the annealing treatment on the surface of the monocrystalline silicon carbide substrate by using the femtosecond laser are that the femtosecond laser has the wavelength of 1030 nm, the repetition frequency of 200 kHz, the pulse width of 260 fs, the laser flux of 0.49-0.61J/cm 2 , the scanning speed of 10-100 mm/s and the scanning interval of 5-20 mu m.
  2. 2. The method of improving electrical properties of a silicon carbide-metal composite interface as claimed in claim 1, wherein the single crystal silicon carbide substrate of step 1) is one of an N-type 4H-SiC substrate, a 3C-SiC substrate, and a 6H-SiC substrate.
  3. 3. The method for improving electrical properties of a silicon carbide-metal composite interface as set forth in claim 1, wherein the annealing of the surface of the single crystal silicon carbide substrate with the femtosecond laser in step 2) is performed under the process conditions of a femtosecond laser wavelength of 1030 nm, a repetition rate of 200 kHz, a pulse width of 260 fs, a laser flux of 0.6J/cm 2 , a scanning speed of 50 mm/s, and a scanning pitch of 10 μm.
  4. 4. The method for improving electrical properties of a silicon carbide-metal composite interface according to claim 1, wherein the step 2) of preparing the metal layer on the surface of the single crystal silicon carbide substrate is performed by vacuum evaporation.
  5. 5. The method for improving electrical properties of a silicon carbide-metal composite interface according to claim 1, wherein the metal layer is a gold electrode layer with a thickness of 50-100 nm.
  6. 6. Semiconductor device obtainable by a method according to any of claims 1-5.

Description

Method for improving electrical property of silicon carbide-metal composite interface Technical Field The invention belongs to the technical field of semiconductor devices, and particularly relates to a method for improving electrical properties of a silicon carbide-metal composite interface. Background The development of semiconductor science and technology has promoted the progress and the revolution in various fields of the current society, and semiconductor materials are also the basis of computer, network and communication technologies. Starting from the first generation of semiconductor silicon materials, as the industry continues to advance and mature, breakthrough in material properties is continually sought to accommodate the needs of different fields. Silicon carbide is one of the representatives of the third-generation semiconductor materials, and has excellent physical and chemical stability, so that the silicon carbide has wide application prospect in the field of high-frequency high-power devices. However, the silicon carbide is limited by complex surface states, and polyunsaturated dangling bonds exist on the surface of the silicon carbide, so that the energy state of a contact interface is changed after the silicon carbide contacts a metal electrode, a schottky barrier is generated, and the stability of a device is greatly influenced. The existing processing means often obtain relatively stable contact interface properties by increasing carrier concentration or reducing schottky barrier, and the corresponding methods are ion implantation and high-temperature annealing, however, the ion implantation inevitably causes lattice distortion or deletion of materials, the high-temperature annealing also causes certain damage to non-modified areas of the device, and the service life of the device is also influenced, so that it is very necessary to develop a new method for improving the electrical properties of the contact interface between silicon carbide and metal. Disclosure of Invention The technical problem to be solved by the invention is to provide a method for improving the electrical property of a silicon carbide-metal composite interface aiming at the defects in the prior art, and the annealing treatment is carried out on the surface of a silicon carbide material by optimizing the technological parameters by utilizing the femtosecond laser technology, so that the obtained annealing surface not only has higher carrier concentration and conductivity, but also ensures the stability of a non-modified area structure by the space selectivity of the femtosecond laser, and the method is simple to operate. In order to solve the technical problems, the technical scheme provided by the invention is as follows: the method for improving the electrical property of the silicon carbide-metal composite interface comprises the following specific steps: 1) Cleaning and drying the monocrystalline silicon carbide substrate to obtain a clean monocrystalline silicon carbide substrate; 2) And (2) placing the clean monocrystalline silicon carbide substrate obtained in the step (1) on a laser galvanometer processing platform, carrying out annealing treatment on the surface of the monocrystalline silicon carbide substrate by using a femtosecond laser, and preparing a metal layer on the surface of the monocrystalline silicon carbide substrate according to requirements after the annealing treatment is finished. According to the scheme, the monocrystalline silicon carbide substrate in the step 1) is one of an N-type 4H-SiC substrate, a 3C-SiC substrate and a 6H-SiC substrate. According to the scheme, the annealing treatment process of the surface of the monocrystalline silicon carbide substrate by using the femtosecond laser in the step 2) is carried out under the process conditions that the femtosecond laser wavelength is 1030nm, the repetition frequency is 200kHz, the pulse width is 260fs, the laser flux is 0.2-1.4J/cm 2, the scanning speed is 10-100 mm/s, and the scanning interval is 5-20 mu m. Preferably, the annealing treatment of the surface of the monocrystalline silicon carbide substrate by the femtosecond laser in the step 2) has the process conditions of 1030nm of femtosecond laser wavelength, 200kHz of repetition frequency, 260fs of pulse width, 0.6J/cm 2 of laser flux, 50mm/s of scanning speed and 10 μm of scanning interval. According to the scheme, the method for preparing the metal layer on the surface of the monocrystalline silicon carbide substrate in the step 2) is to adopt a vacuum evaporation mode for preparation. Preferably, the metal layer is a gold electrode layer, and the thickness is 50-100 nm. The invention also comprises a semiconductor device obtained by the method. According to the invention, the femtosecond laser annealing is utilized to induce phase change on the SiC surface through photochemical reaction, so that the original Si-C bond on the material surface is opened to generate plasma, w