Patent ID: 6084264
Filing Date: 2000-07-04
Classification: H01L

Abstract:
A power MOSFET comprising:a semiconductor substrate of a first conductivity type;an epitaxial layer overlying the substrate, the epitaxial layer being generally of a second conductivity type opposite to the first conductivity type, a trench being formed in the epitaxial layer; anda gate positioned in the trench and electrically isolated from the epitaxial layer by an insulating layer which extends along a bottom and a sidewall of the trench;the epitaxial layer comprising:a source region of the first conductivity type, the source region being located adjacent a top surface of the epitaxial layer and the sidewall of the trench;a body of the second conductivity type adjoining a portion of the sidewall of the trench; anda drain region of the first conductivity type extending downward from the bottom of the trench and merging with first conductivity dopant of the substrate, wherein the body extends downward to form a first PN junction with the first conductivity dopant of the substrate and a second PN junction with the drain region, the second PN junction extending between the first PN junction and the sidewall of the trench.