Patent ID: 7642178
Filing Date: 2010-01-05
Classification: H01L

Abstract:
1. A method for manufacturing a semiconductor device comprising steps of: forming a first epitaxial film having a first conductive type on a silicon substrate having the first conductive type, wherein the first epitaxial film has an impurity concentration lower than that of the silicon substrate; forming a trench in the first epitaxial film; and forming a second epitaxial film having a second conductive type on the first epitaxial film and in the trench so that the trench is filled with the second epitaxial film, wherein the step of forming the second epitaxial film includes a final step, in which a mixed gas of a silicon source gas and a halide gas is used for forming the second epitaxial film, the silicon substrate has an arsenic concentration as the impurity concentration therein, which is defined as α cm the second epitaxial film has an impurity concentration, which is defined as β cm the arsenic concentration in the silicon substrate and the impurity concentration in the second epitaxial film has a relationship of: