Low-temperature Oxidation of Semiconductor Surfaces by use of a Novel High-density Microwave Plasma Apparatus

Abstract

This paper describes a new microwave plasma oxidation apparatus with unique features addressing the near room temperature low temperature process for forming high quality dielectrics with minimum dopant deactivation and redistribution. With this new technique the oxide growth rate was studied as a function of time, gaseous ambient, pressure, applied microwave power and silicon substrate parameters to determine crystallographic oxidation rate anisotropy and dopant concentration dependent oxidation at temperatures much below 400 {degree sign}C. Furthermore, the plasma oxide was also electrically evaluated (C-V- and I-V curves) after as grown, a post plasma anneal up to maximum temperature of 700 {degree sign}C and a post-metallization forming gas anneal. The breakdown strength improved considerably up to 7 MV/cm and the interface trap density decreased much below 10^11 states/eVcm2 so that the oxide quality is comparable to thermal oxides.