Method for insulating a semiconductor material in a trench from a substrate

Abstract

A semiconductor structure is disclosed. In one embodiment, the trench is formed in a substrate, including an upper portion and a lower portion, the upper portion including a lateral dimension larger than a lateral dimension of the lower portion. The lower portion is lined with a first insulating layer and is at least partially filled with a semiconductor material. The first insulating layer extends into the upper portion. A second insulating layer covers, at least partially, the substrate, a portion of the first insulating layer extending into the upper portion and the semiconducting material in the lower portion.

1 . A semiconductor structure comprising:
 a trench being formed in a substrate, comprising an upper portion and a lower portion, the upper portion comprising a lateral dimension larger than a lateral dimension of the lower portion, wherein the lower portion is lined with a first insulating layer and is at least partially filled with a semiconductor material, the first insulating layer extending into the upper portion; and a second insulating layer covering, at least partially, the substrate, a portion of the first insulating layer extending into the upper portion and the semiconducting material in the lower portion.   
     
     
         2 . A semiconductor device comprising:
 a trench being formed in the substrate, comprising an upper portion and a lower portion, the upper portion comprising a lateral dimension larger than a lateral dimension of the lower portion, wherein the lower portion is lined with a first insulating layer and, at least partially, filled with a semiconducting material, forming an at least first electrode, the first insulating layer extending into the upper portion; a second insulating layer covering, at least partially, the substrate, the portion of the first insulating layer extending into the upper portion and the semiconducting material in the lower portion; and an at least second electrode in the substrate.   
     
     
         3 . The semiconductor device as claimed in  claim 2 , wherein the second insulating layer covers, at least partially, the sidewalls of the upper portion and the semiconducting material, forming an at least first electrode. 
     
     
         4 . The semiconductor device as claimed in  claim 2 , wherein the upper portion of the trench is filled with a second insulating layer. 
     
     
         5 . The semiconductor device as claimed in  claim 2 , wherein the lower portion comprises a wall and a bottom and the first insulating layer lines the wall of the lower portion. 
     
     
         6 . The semiconductor device as claimed in  claim 2 , wherein the substrate comprises a second trench laterally shifted to the trench, and wherein a contact hole filled with contacting material between the trench and the second trench forms a contact to the at least second electrode.