Patent ID: 7320908

Claim:
A method of forming a semiconductor device, comprising: etching a semiconductor substrate such that the semiconductor substrate defines a trench and a preliminary active pattern, the trench having a floor and a sidewall; forming an insulating layer on the floor and the sidewall of the trench; forming a spacer on the insulating layer such that the spacer is on the sidewall of the trench and on a portion of the floor of the trench; removing the insulating layer on the floor of the trench and beneath the spacer such that a portion of the floor of the trench is at least partially exposed, the spacer is spaced apart from the floor of the trench and a portion of the preliminary active pattern is partially exposed; partially removing a portion of the exposed portion of the preliminary active pattern to provide an active pattern that defines a recessed portion beneath the spacer; and forming a buried insulating layer in the recessed portion of the active pattern.