Characterization of hot wall RTP for thin gate oxide films

We have developed single-wafer furnace RTP modules for thermal oxidation of silicon substrates. 20 Å dry oxide films were grown on 200 mm diameter Si wafers at 950°C with within-wafer uniformity below 0.6% and wafer-to-wafer uniformity 0.5% (1σ standard deviation, 49 points with 1.5 mm edge exclusion) for 10 successive runs. Wet oxidation at 850°C provides 25 Å oxide films with uniformity below 0.8% (1σ). Thermal nitridation in nitric oxide (NO) and reoxidation can provide sub 25 Å oxides. For a 25 wafer repeatability experiment using 300 mm wafers, the average within wafer standard deviation of the thickness for a 20 Å gate oxide was 0.5% (1σ, 49 points with 3 mm edge exclusion). The thermal stress within the silicon wafer is maintained at low levels shown with both in-situ thermal data and from post-process inspection. It is demonstrated that thin gate oxide films can be generated without the drawbacks associated with lamp based systems.