Influence of crystal originated particles on gate oxide breakdown

Defects causing gate oxide breakdown in Czochralski silicon were evaluated using a location marking technique by Copper plating. The cross sectional structure of the defect was observed by a combination technique of focused ion beam (FIB) etching at the marked location and transmission electron microscopy (TEM) and found to have similar appearances and sizes to those of crystal originated particles (COPs) observed by atomic force microscopy (AFM). Correlation between locations of the defects at a wafer surface determined using the copper plating and those of COPs determined using a particle counter was investigated for various electric field applied for the copper plating. We found that COPs are one of the major factors causing gate oxide breakdown at fields around 4MV/cm, while other factors become dominant when a higher electric field is applied.