Semiconductor device

Abstract

A semiconductor device includes a semiconductor substrate, an insulating member provided on the semiconductor substrate and an electrode disposed on the semiconductor substrate and on the insulating member. The insulating member includes a plurality of first portions and a plurality of second portions thinner than the first portions. The first portions and the second portions are arranged alternately along a first direction, the first direction being parallel to a region of an upper surface of the semiconductor substrate not contacting the insulating member.

What is claimed is: 
     
         1 . A semiconductor device, comprising:
 a semiconductor substrate;   an insulating member provided on the semiconductor substrate; and   an electrode provided on the semiconductor substrate and on the insulating member,   the insulating member including
 a plurality of first portions, and 
 a plurality of second portions thinner than the first portions, 
   the first portions and the second portions being arranged alternately along a first direction, the first direction being parallel to a region of an upper surface of the semiconductor substrate not contacting the insulating member.   
     
     
         2 . The device according to  claim 1 , wherein
 an upper surface of the first portion is positioned lower than an upper surface of the second portion, and   a lower surface of the first portion is positioned lower than a lower surface of the second portion.   
     
     
         3 . The device according to  claim 1 , wherein
 not less than half of the insulating member in a vertical direction is disposed inside the semiconductor substrate, and   a region of an upper surface of the insulating member is not covered with the semiconductor substrate.   
     
     
         4 . The device according to  claim 1 , wherein not less than half of the insulating member in a vertical direction is positioned higher than the region of the upper surface of the semiconductor substrate not contacting the insulating member. 
     
     
         5 . The device according to  claim 1 , wherein the electrode includes a band-shaped portion, two side surfaces of the band-shaped portion extending in linear configurations in the first direction. 
     
     
         6 . The device according to  claim 1 , wherein
 the electrode includes:
 a base portion extending in the first direction, and 
 a plurality of tooth portions extending from the base portion in a second direction crossing the first direction, and 
   in a vertical direction, the tooth portions overlap the first portions, and the second portion is positioned between the tooth portions.   
     
     
         7 . The device according to  claim 1 , further comprising a gate insulating film provided between the semiconductor substrate and the electrode, the gate insulating film being thinner than the second portion. 
     
     
         8 . The device according to  claim 1 , further comprising:
 a source layer provided on the semiconductor substrate, the source layer being of a first conductivity type; and   a drain layer provided on the semiconductor substrate, the drain layer being of the first conductivity type,   at least an upper layer portion of the semiconductor substrate being of a second conductivity type,   the insulating member being disposed between the drain layer and the source layer or in a region directly above a region between the drain layer and the source layer.   
     
     
         9 . The device according to  claim 8 , wherein a direction from the source layer toward the drain layer is a second direction crossing the first direction. 
     
     
         10 . A semiconductor device, comprising:
 a semiconductor substrate;   a plurality of insulating members provided on the semiconductor substrate and arranged to be separated from each other along a first direction; and   an electrode disposed on the semiconductor substrate and on the plurality of insulating members,   the electrode including
 a base portion extending in the first direction, and 
 a plurality of tooth portions extending from the base portion in a second direction crossing the first direction, 
   in a vertical direction, the insulating members overlapping the tooth portions, and a region between the insulating members overlapping a region between the tooth portions.   
     
     
         11 . The device according to  claim 10 , wherein not less than half of the insulating member in the vertical direction is positioned higher than a region of an upper surface of the semiconductor substrate not contacting the insulating member. 
     
     
         12 . The device according to  claim 10 , further comprising a gate insulating film provided between the semiconductor substrate and the electrode, the gate insulating film being thinner than the insulating member. 
     
     
         13 . The device according to  claim 10 , further comprising:
 a source layer provided on the semiconductor substrate, the source layer being of a first conductivity type; and   a drain layer provided on the semiconductor substrate, the drain layer being of the first conductivity type,   at least an upper layer portion of the semiconductor substrate being of a second conductivity type,   the insulating member being disposed between the drain layer and the source layer or in a region directly above a region between the drain layer and the source layer.   
     
     
         14 . The device according to  claim 13 , wherein a direction from the source layer toward the drain layer is a second direction crossing the first direction.