Low-on-resistance trench silicon carbide power device and manufacturing method thereof

Abstract

The invention discloses a low-on-resistance trench silicon carbide power device and a manufacturing method thereof. The cellular structure comprises an N-type substrate, an N-type epitaxial layer anda trench; a graphene layer is arranged on the side wall of the trench; a gate oxide layer and a polycrystalline silicon gate are arranged in the trench; a passivation layer is arranged above the polycrystalline silicon gate; a P-type body region, an N-type source region and a P-type body contact region are arranged on the two sides of the trench; a P-type shielding layer is arranged below the graphene layer; source metal is arranged on the upper surface of the source region; and drain metal is arranged on the lower surface of the substrate. According to the power device, an electron beam method is used, metal and a carbon source gas are used for assisting, and the graphene layer grows on the side wall of the trench. The power device is characterized in that the graphene layer on the side wall of the trench reduces the on resistance. The shielding layer below the graphene layer shields the current flowing through the graphene layer when the device is in an off state, and the turn-off characteristic of the device is improved. The growth of the graphene layer is assisted by metal nickel and the carbon source gas, so that the uniformity, the thickness and the growth rate of the graphene layer are improved.

Description

technical field [0001] The invention belongs to the technical field of structure design and manufacture of power semiconductor devices, and at the same time relates to a manufacturing technology of two-dimensional materials on a wide bandgap semiconductor substrate, specifically a new type of grooved silicon carbide with low on-resistance characteristics Power devices and methods of manufacturing the same. Background technique [0002] Silicon carbide has excellent electrical and thermal properties and is considered to be the most promising third-generation semiconductor material to replace silicon in the field of power electronics. Although the manufacturing process of silicon carbide devices has gradually matured and some products have been commercialized, the channel electron mobility of silicon carbide power devices is greatly reduced due to the existence of a large number of interface states between the silicon carbide semiconductor and the silicon dioxide oxide layer. ...

AI Technical Summary

Problems solved by technology

Although the manufacturing process of silicon carbide devices has gradually matured and some products have been commercialized, the channel electron mobility of silicon carbide power devices is greatly reduced due to the existence of a large number of interface states between the silicon carbide semiconductor and the silicon dioxide oxide layer. Reduced, can not play the full performance of silicon carbide material

Graphene is a two-dimensional electronic material with high electron mobility, which can be directly grown on silicon carbide substrates. Applying graphene to the field of silicon carbide power devices can greatly reduce the on-resistance of silicon carbide power devices, but It will increase the shutdown current of the device and affect the shutdown characteristics of the device

Moreover, using the traditional silicon carbide epitaxial growth method to manufacture graphene layers requires a high temperature environment above 1400 ° C, which is incompatible with the manufacturing process of silicon carbide power devices, and the chemical vapor deposition method involves wet transfer of graphene layers. The process is difficult and easy to introduce pollution

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