Thin Nitride Films: Pushing the Limits Using Rapid Thermal Processing

Abstract

AbstractSilicon nitride, a celebrated dielectric material in semiconductor processing, is used extensively in almost all of today's key technologies (DRAM, microprocessor, SRAM, Flash memories, etc.). The physical and electrical properties of this material are well understood, and integration of silicon nitride in a given process is simple. As a result of these benefits, alternate dielectric material technologies have found limited acceptance. As feature sizes shrink, the formation of reliable thin nitride films is critical and the performance of these nitride films is very dependent on the technology used for their preparation. In this paper, we show that an incremental and overall improvement in the physical and electrical properties of nitride films can be attained by using rapid thermal processing technology.We present the nucleation behavior of the <100 Å nitride films on polysilicon surfaces. We investigate the integrity of these films as a function of predeposition environment and discuss the oxidation and punch-through resistance of cluster tool-deposited films. The results of our studies of the conduction mechanism in thin silicon nitride films and scaling limits for these films are shown. We also discuss the structural and electrical changes these films undergo during the subsequent reoxidation process performed for leakage current reduction.