公开(公告)号：JPH10242415A

公开(公告)日：1998-09-11

申请号：JP1839798

申请日：1998-01-30

Applicant: IBM

Inventor： HALLE SCOTT D ,  HWANG CHORNGLII ,  MULLER PAUL K

IPC: H01L27/108 ,  H01L21/02 ,  H01L21/8242

Abstract: PROBLEM TO BE SOLVED: To increase the surface area of a side wall without increasing the depth of a trench by using the granular structure of polysilicon with the anisotropic etching and making the trench side wall into a rough face so that it can be controlled. SOLUTION: A trench color 6 is formed by using a thermal oxidation method and oxidized nitride is removed by isotropic etching. The isotropic etching of silicon is executed after the color oxide 6 is formed, and the rough face degree of polysilicon is improved. During etching, amorphous silicon or a polysilicon layer 4 at the lower side of the color 6 is etched into a silicon substrate 2 through the trench side wall. The side wall and the base part of the trench 1, which are at the lower side of the color oxide 6, are provided with a rough face layer as the result of etching. The trench side wall is made into the rough face by means of the granular structure of polysilicon and the preferential etching of granular boundary. Then, the rough face degree can be controlled by using isotropic etching.