IMPACTING DEVICE PERFORMANCE AND YIELD THROUGH SACRIFICIAL OXIDATION IMPROVEMENTS

摘要

Formation of trenches in silicon, the silicon-oxide interface integrity, and process-induced effects and its associated bulk substrate properties are critical to device performance. Sharp trench corners and rough silicon surface result in electric field concentration and stress, leading to device performance degradation. A high temperature sacrificial oxidation is found to be very effective in rounding off trench top corners and improving the silicon surface roughness. In addition, a H_2/N_2 forming gas anneal is found to improve the yield. The higher sacrificial oxidation temperature resulted in enhanced oxidation at trench corners and reduced stress. It is suggested that a forming gas anneal combined with a 1100℃ sacrificial oxidation could be effective in improving performance and yield for devices utilizing trench technology.