Patent ID: 8722434

Claim:
A method for manufacturing an integrated circuit comprising a pair of trench MOSFET and trench Schottky rectifier horizontally disposed in two different areas in said integrated circuit, comprising the steps of; growing an epitaxial layer with a first conductivity type upon a heavily doped substrate with said first conductivity type; etching a plurality of first gate trenches in said trench MOSFET, and a plurality of second gate trenches in said trench Schottky rectifier after applying a trench mask; refilling said first and second gate trenches with a doped poly-silicon layer padded by a gate oxide layer; applying a body mask and carrying out ion implantation with a second conductivity type dopant and then diffusing it to form body regions; applying a source mask and carrying out ion implantation with said first conductivity type dopant to form source regions with heavier doping concentration than said epitaxial layer; forming an insulation layer covering top surface of said trench MOSFET and said trench Schottky rectifier; applying a contact mask onto said insulation layer; etching a plurality of contact trenches by successively dry oxide etching and dry silicon etching, wherein said contact trenches include: a plurality of source-body contact trenches penetrating through said insulation layer, said source regions and extending into said body regions; and a plurality of anode contact trenches penetrating through said insulation layer and extending into said epitaxial layer; forming a body contact region of said second conductivity type with heavier doping concentration than said body regions underneath bottom of each of said source-body contact trenches; and carrying out ion implantation with said second conductivity dopant to form an avalanche enhancement region wrapping sidewall of each of said source-body contact trenches in said trench MOSFET within said body regions, and a Schottky barrier enhancement region wrapping sidewall and bottom of each of said anode contact trenches in said trench Schottky rectifier within said epitaxial layer.