Method of manufacturing vertical planar power MOSFET and method of manufacturing trench-gate power MOSFET

摘要

In the manufacturing steps of a super-junction power MOSFET having a drift region having a super junction structure, after the super junction structure is formed, introduction of a body region and the like and heat treatment related thereto are typically performed. However, in the process thereof, a dopant in each of P-type column regions and the like included in the super junction structure is diffused to result in a scattered dopant profile. This causes problems such as degradation of a breakdown voltage when a reverse bias voltage is applied between a drain and a source and an increase in ON resistance. According to the present invention, in a method of manufacturing a silicon-based vertical planar power MOSFET, a body region forming a channel region is formed by selective epitaxial growth.

主权项

1. A method of manufacturing a vertical planar power MOSFET comprising:
(a) a silicon-based semiconductor substrate having a first main surface and a second main surface; (b) a drift region having a super junction structure in which a column region of a first conductivity type and a column region of a second conductivity type which are provided in the semiconductor substrate are alternately and repeatedly formed; (c) a drain region of the first conductivity type provided in a semiconductor back surface area of the semiconductor substrate closer to the second main surface; (d) a metal drain electrode provided over the second main surface of the semiconductor substrate; (e) a body region of the second conductivity type provided in a semiconductor top surface area of the semiconductor substrate closer to the first main surface; (f) a source region of the first conductivity type which is the semiconductor top surface area of the semiconductor substrate closer to the first main surface and provided in the body region; (g) a gate electrode provided over the first main surface of the semiconductor substrate via a gate insulating film; and (h) a metal source electrode provided over the first main surface of the semiconductor substrate so as to be electrically coupled to the source region, the method of manufacturing the vertical planar power MOSFET comprising the steps of: (x1) forming the super junction structure on the top surface side of the silicon-based wafer of the first conductivity type; (x2) forming a trench to be filled with the body region for embedding the body region in a surface of the super junction structure; and (x3) filling the trench to be filled with the body region by selective epitaxial growth.