Optimization and Stress Analysis of Local Oxidation of Silicon (LOCOS) Process for Isolation

This paper presents the optimization and stress analysis of LOCOS process using Athena TCAD. Various process parameters in LOCOS like pad oxide(buffer oxide), nitride thickness, field oxidation temperature and time has been considered for simulation. Experimental results on LOCOS process development based on sputtered silicon nitride(Si₃N₄) and effect of stress on bird beak formation is also presented. The effect of annealing on sputtered silicon nitride at different temperatures on stress has also been measured which provides the way to compare simulated results with experimental data. Our optimized results clearly demonstrate that the stress generated at the interface immensely influence the bird beak formation resulting in loss of active area.