Improvement of ultra-thin 3.3 nm thick oxide for Co-salicide process using NF ₃ annealed poly-gate

To get high quality ultra-thin oxide is very important and difficult for IC industry now. Using NF₃ annealed poly-Si gate to improve gate oxide integrity is described. However, reducing gate, source and drain parasitic resistance with gate lengths down to 0.2 μm is another key point. Co-salicide process can successfully reduce the gate resistance even for a gate length of 0.075 μm. Although, Co-salicide process has a leakage problem. Using NF₃ annealing to prevent Co diffusing into gate oxide is described too. Results show that the optimal NF₃ annealing significantly improves electrical characteristics of ultra-thin oxide and Co-salicide process in terms of leakage current and breakdown field, as compared to the samples without NF₃ annealing.