Effect of the pre-gate oxide cleaning temperature on the reliability of GOI and devices performances in deep submicron CMOS technology

This paper reports the impacts of the pre-gate oxide cleaning on the statistic fluctuations of a deep submicron CMOS devices’ saturation current, leakage current, threshold voltage, and gate oxide integrity (GOI) in detail. These statistic distributions are based on a foundry’s batch production line. This study concludes that the pre-gate oxide hot water clean enhances silicon surface’s micro-roughness and stress effects, thus are responsible to the higher fluctuations of devices performance distributions. Similar results were found in the GOI of the thin gate oxide. The micro-roughness and stress effects of silicon surface were evaluated systematically through atom force microscope (AFM) and thin film stress measurement system, and their mechanisms are interpreted comprehensively with schematic models.