Abstract: The method for forming an isolation film in a semiconductor device includes the steps of providing a semiconductor substrate having at least a first insulation film formed thereon, and forming a trench in the first insulation film and the semiconductor substrate. Next, an insulation film pattern is formed. The insulation film pattern fills the trench and extends from the trench over a portion of the first insulation film. Afterwards, the first insulation film is etched. The etching of the first insulation film also results in etching of the insulation film pattern, but the insulation film pattern at the upper side wall edges of the trench is not etched.

Abstract: In the method of manufacturing an epitaxial silicon wafer, a silicon wafer substrate is hydrogen-annealed to remove impurities and defects. Then, an impurity buried layer is formed in an upper surface of the silicon wafer substrate. The impurity buried layer increases the number of contaminant attractors in the upper surface of the silicon wafer substrate. As a result, during the subsequent formation of a silicon epitaxial layer, the contaminant attractors attract contaminants away from the silicon epitaxial layer.