Fabrication method of grooved MOSFET devices based on two-step microwave plasma oxidation

Abstract

A method of manufacturing a grooved-gate MOSFET device based on a two-step microwave plasma oxidation, including: etching a grooved gate, and oxidizing silicon carbide on a surface of the grooved gate to silicon dioxide by microwave plasma to form a grooved-gate oxide layer, the step of forming the grooved-gate oxide layer including: placing a silicon carbide substrate subjected to the grooved gate etching in a microwave plasma generating device; introducing a first oxygen-containing gas, heating generated oxygen plasma to a first temperature at a first heating rate, and performing low-temperature plasma oxidation at the first temperature and a first pressure; heating the oxygen plasma to a second temperature at a second heating rate, introducing a second oxygen-containing gas, and performing high-temperature plasma oxidation at the second temperature and a second pressure until a predetermined thickness of silicon dioxide is formed; stopping introduction of the oxygen-containing gas, and completing the reaction.

Description

technical field [0001] The invention belongs to the technical field of semiconductors, and in particular relates to a method for manufacturing a groove MOSFET device based on two-step microwave plasma oxidation. Background technique [0002] Silicon carbide (SiC) is the third-generation semiconductor-wide bandgap semiconductor material. It has the advantages of large bandgap width, high critical breakdown field strength, and high thermal conductivity. It is an ideal material for making high-voltage and high-power semiconductor devices. SiC power Electronic devices are at the heart of next-generation high-efficiency power electronics technology. Compared with Si MOSFETs, SiC MOSFETs have smaller on-resistance, higher switching voltage, higher application frequency, and better temperature performance, and are especially suitable for power switching applications. The integrated manufacturing process of SiC MOSFET devices, especially the gate dielectric process, is a current re...

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Problems solved by technology

However, due to the thermal oxidation growth of SiO on the sidewall 2 The rate is several times that of the bottom oxidation rate, which makes the device unable to turn on when the gate voltage of the device reaches the maximum safe operating voltage of the gate oxide, and the channel region on the sidewall cannot be turned on because the gate voltage does not reach the threshold voltage, and the forward characteristic cannot be obtained. If the gate voltage continues to increase, the stability of the bottom gate oxide will deteriorate, causing premature breakdown of the bottom oxide layer, and the device cannot work normally.

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