OPTIMIZATION OF MANUFACTURING METHODOLOGY: P-CHANNEL TRENCH MOS WITH LOW VTH AND N-TYPE POLY

摘要

A method for forming a trench MOSFET includes doping a body region of the trench MOSFET in multiple ion implantation steps each having different ion implantation energy. The method further comprises etching the trench to a depth of about 1.7 μm.

主权项

1. A method of forming a trench MOSFET, the method comprising:
forming a drain region in a semiconductor substrate; forming a body region in the semiconductor substrate above the drain region, forming the body region including:
implanting dopant atoms in the body region of the semiconductor substrate with a first implantation energy;implanting dopant atoms in the body region of the semiconductor substrate with a second implantation energy; andimplanting dopant atoms in the body region of the semiconductor substrate with a third implantation energy; andimplanting dopant atoms in the body region of the semiconductor substrate with a fourth implantation energy; implanting dopant atoms in a source region of the semiconductor substrate above the body region; and forming a trench in the semiconductor substrate, a sidewall of the trench abutting the source, body, and drain regions, the body region having a substantially constant doping concentration along the sidewall of the trench between the source and drain regions.