Method for fabricating semiconductor device with reduced Miller capacitance

摘要

A method for fabricating a semiconductor transistor device. An epitaxial layer is grown on a semiconductor substrate. A gate trench is formed in the epitaxial layer. A spacer is formed on a sidewall of the gate trench. A recess is formed at the bottom of the gate trench. A thermal oxidation process is performed to form an oxide layer in the recess. The oxide layer completely fills the recess. The spacer is then removed. A gate oxide layer is formed on the exposed sidewall of the gate trench. A gate is then formed into the gate trench.

主权项

1. A method for fabricating a semiconductor transistor device, comprising:
providing a semiconductor substrate having a first conductivity type; forming an epitaxial layer on the semiconductor substrate; etching the epitaxial layer to thereby form a gate trench in the epitaxial layer; after forming the gate trench, forming a spacer on a sidewall of the epitaxial layer within the gate trench; etching the epitaxial layer from a bottom surface of the gate trench to form a recess underneath the gate trench; performing a thermal oxidation process to form an oxide layer that only fills up the recess; removing the spacer; forming a gate oxide layer on an exposed sidewall of the gate trench; and forming a gate in the gate trench.