Lead: This patented manufacturing method of silicon carbide Schottky diodes increases the area of the anode contact area of the Schottky diode and reduces the on-resistance of electronic components on the basis of ensuring the blocking voltage.
Affected by the expansion of the application field of SiC (silicon carbide) semiconductors, the favorable macroeconomic policies of the industry, the pursuit of capital markets, and the active promotion of local governments, the domestic third-generation semiconductor industry is advancing rapidly. On March 29, 2019, Tyco Tianrun Semiconductor The 6-inch semiconductor silicon carbide power electronic device production line project invested and constructed by Science and Technology (Beijing) Co., Ltd. was officially signed and settled in Jiujiang Economic Development Zone. Inject new momentum into Jiujiang City to build a 100 billion electronic and electrical industry cluster and grow the first industry in the Economic Development Zone. Actively develop the manufacturing process of semiconductor power devices on SiC wafers.
It is understood that Tyco Tianrun Semiconductor Technology (Beijing) Co., Ltd. is the first domestic high-tech enterprise dedicated to the manufacture of third-generation semiconductor material silicon carbide (SiC) power electronic devices. It is headquartered in Zhongguancun, Beijing, China. A complete semiconductor process wafer factory that can realize the manufacturing process of semiconductor power devices on 4-inch SiC wafers, and has the only silicon carbide device production line in China.
The project has a total investment of 1 billion yuan to build a 6-inch semiconductor silicon carbide power electronic device production line in Chengxi Port District, with a planned production capacity of 60,000 pieces/year. After the project is fully produced, it is expected to achieve an annual output value of 1.05 billion yuan. The project belongs to the semiconductor industry encouraged by the country and is a strategic emerging industry project that my country will focus on in the near future. The project will build the country's first internationally advanced SiC power device production line, filling the gap in semiconductor power devices in Jiujiang and even Jiangxi Province.
In the field of electronic devices, Schottky diodes are widely used in analog circuits and large-scale integrated circuits. They have the characteristics of short reverse recovery time and extremely small reverse recovery charge. The efficiency improvement of electronic devices widely depends on the development of semiconductor materials. As an emerging third-generation semiconductor material, silicon carbide has good physical and electrical properties. With its wide band gap, high thermal conductivity and high critical electric field, it has become an ideal material for high-temperature, high-power, and high-frequency semiconductor devices. , Therefore promoted the development of Schottky barrier diodes and junction barrier diodes. The Schottky diode uses the space charge region of the reverse biased PN junction to bear the reverse bias voltage for the SBD structure, so that on the basis of ensuring the blocking voltage, the Schottky barrier height can be appropriately reduced to reduce the forward voltage drop. Reduce diode reverse bias leakage. However, in the junction barrier Schottky diode, the ion-implanted junction area cannot conduct electricity, so the effective conduction area of the device is reduced. This shortcoming limits the improvement of the conduction current density of the JBS device.
In order to solve this problem, Tyco Tianrun proposed an invention patent named "A silicon carbide Schottky diode and its preparation method" on February 12, 2018 (application number: 201810145243.2). The applicant is Tyco Tianrun Semiconductor Technology (Beijing) Co., Ltd.
This patent provides a silicon carbide Schottky diode and a preparation method thereof. The trench structure is used to increase the anode contact area of the Schottky diode on the basis of ensuring the blocking voltage and reduce the on-resistance of the device.
The cross-section of the silicon carbide Schottky diode proposed in this patent is shown in FIG. 1, and includes an anode metal 5, a p-type epitaxial layer 3, an n-type drift layer 2, an n+ substrate 1 and a cathode metal 6 arranged sequentially from top to bottom. A plurality of grooves are provided on the p-type epitaxial layer 3, and a plurality of protrusions 7 are provided on one side of the anode metal 5, and the grooves are matched with the protrusions. The thickness of the n-type epitaxial layer is 5um to 200um, the thickness of the p-type epitaxial layer 3 is 0.3um to 1.5um, and the doping concentration of the n-type epitaxial layer is greater than the doping concentration of the p-type epitaxial layer. The cathode metal is Ni, and the anode metal is Al or Ti to better form the anode contact. The metal forms a Schottky contact with the n-type drift layer 2 and an ohmic contact with the p-type epitaxial layer 3, so that when the device is reversely blocked At this time, the depletion layer formed by the n-type drift layer 2 and the p-type epitaxial layer 3 can shield the sides of the trench 4 to the greatest extent and reduce the leakage current in the blocking state.
Figure 2 Flow chart of the manufacturing method of silicon carbide Schottky diode
The manufacturing method of the silicon carbide Schottky diode is shown in Figure 2. First, an n-type drift layer is grown on the n+ substrate 1, and a p-type epitaxial layer is formed on one side of the n-type drift layer by epitaxial growth. Then, the electron beam evaporation method is used on the surface of one side of the p-type epitaxial layer to evaporate to form a mask layer with a predetermined thickness, and the mask layer and the oxide layer are used to form a trench. Then a metal is deposited on the other side of the n-type drift layer 2 by electron beam evaporation or magnetron sputtering, and the cathode metal is formed by annealing; on the side of the p-type epitaxial layer 3, by electron beam evaporation or magnetron sputtering A metal is deposited, the trench is filled, and the field plate pattern is formed by photolithography and etching. Then, contact annealing is performed under the protection of nitrogen to form the anode metal 5, and finally a complete silicon carbide Schottky diode is formed.
Meirui Electronics (0769-21665206) is the agent of Tyco Tianrun. Welcome to inquire about silicon carbide Schottky diodes, silicon carbide MOSFETs and silicon carbide modules related electronic components.