Patent ID: 7151290
Filing Date: 2006-12-19
Classification: H01L

Abstract:
1. A semiconductor device comprising: a semiconductor substrate; an element separation insulating film; a diffusion layer which is formed around a bottom of a trench formed in a surface of the semiconductor substrate; a first insulating film provided on an inner surface of the trench, the first insulating film including a capacitor insulating film formed in a lower portion of the trench and a collar oxide film formed in an upper portion of the trench; a conductive film which is filled in the trench and which has a first portion, a second portion and a third portion, the first portion being surrounded by the capacitor insulating film, the second portion being surrounded by the collar oxide film and the element separation insulating film, and the third portion having an upper surface higher than that of the second portion; a second insulating film which is provided on the second portion of the conductive film and which has a first portion and a second portion, the first portion contacting the third portion of the conductive film and having an upper surface lower than the surface of the third portion of the conductive film, the second portion having an upper surface higher than the surface of the semiconductor substrate; a first gate electrode provided on the second insulating film; a second gate electrode provided above the semiconductor substrate away from the first gate electrode; source/drain diffusion layers which are formed in the surface of the semiconductor substrate and which sandwich a channel area under the second gate electrode; and a connection conductive layer extending on the conductive film and on one of the source/drain diffusion layers.