Cellular structure of silicon carbide device, preparation method of cellular structure and silicon carbide device

Abstract

The invention provides a cellular structure of a silicon carbide device, a preparation method of the cellular structure and the silicon carbide device. The cellular structure comprises a plurality ofsecond conductive type well regions arranged in the surface of a drift layer at intervals, a second conductive type first source region and a first conductive type second source region which are located in the surface of the well region, first gate trenches located between every two adjacent well regions, a second conductive type first shielding region which is located in the drift layer and located below the first gate trenches, and a first gate and a second gate which are arranged in the first gate trench and are respectively located on two sides of the first gate trench. By arranging the first shielding region at the bottom of the first gate trench, the electric field stress of a gate oxide layer of the device in a blocking state can be greatly reduced, and the long-term use reliabilityof the device is greatly improved. The first gate and the second gate which are isolated by the interlayer dielectric layer are arranged in the gate trench to form a split gate, so that the parasiticcapacitance of the gate can be reduced.

Description

technical field [0001] The present disclosure relates to the technical field of semiconductor devices, in particular to a cell structure of a silicon carbide device, a preparation method thereof, and a silicon carbide device. Background technique [0002] Silicon carbide (SiC) is a new wide-bandgap semiconductor material with excellent physical, chemical and electrical properties. The breakdown electric field strength of silicon carbide is 10 times that of traditional silicon, the thermal conductivity is 3 times that of silicon, and it has a higher switching frequency, which can reduce the loss and volume of energy storage components in the circuit. In theory, silicon carbide devices can work in a high temperature environment above 600 °C, and have excellent radiation resistance, which greatly improves their high temperature stability. This makes SiC-based power semiconductor devices very attractive and promising for high-power and high-temperature applications. Among them...

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Problems solved by technology

[0004] In view of the above problems, the present disclosure provides a cell structure of a silicon carbide device, its preparation method and a silicon carbide device, which solves the problem that the silicon carbide device in the prior art is in the blocking state due to the concentrated electric field that damages the gate oxide layer. Technical problems of failure and poor reliability

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