Patent ID: 8258032

Claim:
A method for manufacturing a semiconductor device, the method comprising the steps of: (a) forming a mask on a first major surface of a semiconductor substrate, the mask having an opening formed therein; (b) etching a portion of the semiconductor substrate exposed by the mask opening to form a trench in the first major surface, the trench having side walls and a bottom plane; (c) implanting a dopant into a semiconductor layer at the bottom plane of the trench to form an impurity layer; (d) activating the impurity layer formed in step (c); and (e) filling the trench with a semiconductor; wherein the trench is one of a plurality of trenches having impurity layers at the bottom planes thereof, formed according to steps (a), (b) and (c), and wherein activating the impurity layers according to step (d) causes the impurity layers in adjacent trenches to connect.