Super-junction trench MOSFET structure

摘要

A super-junction trench MOSFET is disclosed by applying a first doped column region of first conductivity type between a pair of second doped column regions of second conductivity type adjacent to sidewalls of a pair of deep trenches with buried voids in each unit cell for super-junction. A buffer poly-silicon layer is deposited above the buried void for stress release to prevent wafer crack and silicon defects.

主权项

1. A super-junction trench MOSFET comprising:
a substrate of a first conductivity type; an epitaxial layer of said first conductivity type grown on said substrate, and said epitaxial layer having a lower doping concentration than said substrate; a pair of deep trenches filled with dielectric material, starting from a top surface of said epitaxial layer and down extending into said substrate, each of said deep trenches comprising a void inside said dielectric material; a buffer poly-silicon layer deposited above said void insolated with said dielectric material; a first doped column region of said first conductivity type with column shape formed in an area between said pair of deep trenches; a pair of second doped column regions of a second conductivity type with column shape formed adjacent to sidewalls of said deep trenches, said first doped column region being formed in parallel and sandwiched between said pair of second doped column regions to form charge balance areas.