Method of preparing silicon carbide MOSFET gate dielectric layer

Abstract

The invention provides a method of preparing a silicon carbide MOSFET gate dielectric layer. The method comprises the following steps of: providing a SiC substrate, and placing the SiC substrate in anALD reaction chamber, raising the temperature of the ALD reaction chamber, sequentially and circularly growing a SiO2 film and an Al2O3 film on the surface of the SiC substrate by adopting an ALD process to form a gate dielectric layer, and performing annealing processing on the formed gate dielectric layer in an oxygen atmosphere. In the growth process of the gate dielectric layer, Si atoms in the SiC epitaxial wafer are not consumed, so that the phenomenon of C group aggregation at the interface of the gate dielectric layer and SiC is avoided, and the interface characteristic is improved; the gate dielectric layer is formed by using the ALD technology, the thermal budget is low, and the device preparation process is simplified; the gate dielectric layer formed by the ALD technology hasthe characteristics of high SiO2 breakdown strength, wide forbidden band width, high thermal stability and high Al2O3 dielectric constant at the same time, the electric field intensity introduced intothe gate dielectric film can be greatly reduced, gate dielectric breakdown is avoided, and gate leakage current is inhibited.

Description

technical field

[0001] The invention belongs to the technical field of semiconductor technology, in particular to a method for preparing a silicon carbide MOSFET gate dielectric layer. Background technique

[0002] As a wide band gap semiconductor material, silicon carbide has excellent characteristics such as wide band gap, high breakdown electric field strength, high electron saturation drift velocity, and high thermal conductivity. Compared with traditional Si-based power devices, SiC power devices can obtain higher breakdown voltage, lower on-resistance, higher operating temperature and faster switching speed. As a new generation of power devices, they have attracted much attention and become International research hotspots in the fields of new materials, microelectronics and optoelectronics.

[0003] At present, SiC SBDs (Schottky diodes) have been widely used in switching power supplies, especially in PFC (power factor correction) circuits to replace traditional Si-ba...

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