Patent ID: 6737706
Filing Date: 2004-05-18
Classification: H01L

Abstract:
A method for manufacturing a semiconductor device comprising:providing a substrate which includes a base layer, a buried oxide layer, and a semiconductor layer; forming a first trench having a depth less than the thickness of the semiconductor layer; forming a second trench having a depth at least equal to the thickness of the semiconductor layer in a bottom portion of the first trench; and forming an oxide layer on the first trench; forming an isolation layer by sequentially forming an oxide liner and a nitride liner along surfaces of the first and second trenches and then forming a dielectric layer to fill the trench, the oxide liner being formed by chemical vapor deposition (CVD), the oxide liner preventing direct contact between the nitride liner and the semiconductor layer, and then forming a dielectric layer to fill the trench; wherein the oxide layer and oxide liner in the first trench is of a thickness that is greater than the oxide liner in the second trench.