SEMICONDUCTOR DEVICE AND MANUFACTURE OF THE SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a fine circular truncated cone whose aspect ratio is large and whose top end effective area is small, and a method for manufacturing the circular truncated cone. SOLUTION: An impurity, for example oxygen, is introduced into a silicon substrate or a silicon layer, and heat treatment is carried out so that an impurity deposition region is formed, and highly selective ratio anisotropic etching is carried out by using the deposition region as a micromask 14. After a circular truncated cone with the micromask 14 as a vertex is formed, the highly selective ratio anisotropic etching is further carried out, so that the upper face of a circular truncated cone 18 is made to expose, and the etching is further continued, and the upper part of the circular truncated cone is etched like a blow, from the upper face of the circular truncated cone 18 toward the bottom face so that the circular truncated cone 18 whose top end is shaped circular can be obtained. The aspect ratio of a bowl shaped part 20 formed on the upper face of the circular truncated cone 18 by over-reaching is set to about 10 similar to that of the circular truncated cone 18, and the width of a circle formed at the top end of the circular truncated cone 18 due to the existence of the bowl shaped part 20 is set at about 1 nm-2 nm.