Patent ID: 6133157
Filing Date: 2000-10-17
Classification: H01L

Abstract:
A method for selectively etching a second silicon layer of a multilayer structure which includes a first silicon layer and a second silicon layer formed on the first silicon layer and doped with impurities, wherein the impurities doped in the second silicon layer are n-type impurities,wherein the second silicon layer is selectively eteched by using an etching gas including a freon-14 gas and a gas selected from a group consisting of hydrogen chloride gas and chorine gas and excluding carbon tetrachloride and hydrogen bromide, and,further wherein, the concentration (mol %) of the freon-14 gas against the gross volume of the freon-14 gas and the gas selected from the group consisting of the hydrogen chloride gas and the chlorine gas and excluding carbon tetrachloride and hydrogen bromide is 67% or more.