Tapered Sidewall Field-Effect Transistor Gates
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
In processing where implantation steps require abrupt sidewalls for definition but the abruptness introduces metallization difficulty, the sidewalls can be tapered by conformal film deposition followed by anisotropic etching. The technique is illustrated in Figs. 1-4 where PECVD is plasma enhanced chemical vapor deposition and the material is one of Si3N4, SiO2, and oxynitride. RIE is reactive ion etch. A 45Œ-50Œ sidewall is formed on the WSi gate.