Nitrogen Doped 300 mm Czochralski Silicon Wafers Optimized with Respect to Voids with Laterally Homogeneous Internal Getter Capabilities

Abstract

An internally gettering bulk defect zone and a defect denuded zone of at least 5 µm below the wafer surface were generated by out-diffusion of interstitial oxygen during annealing at temperatures in the range 1075-1100 °C in argon atmosphere. The CZ silicon material used was optimized with respect to voids and contained a central OSF region and an outer Pv region. Due to co-doping of at least 3×1013cm-3nitrogen, a laterally homogeneous bulk microdefect density was obtained which is independent of the temperature of the out-diffusion anneal. The internal getter created in this way efficiently getters nickel impurities as demonstrated in a getter test with 6.6×1011cm-3of intentional Ni contamination. In the central OSF region of the as-grown nitrogen co-doped wafers, the nuclei capable of generating OSFs also degrade the gate oxide integrity. Out-diffusion annealing at 1075-1100°C dissolves most of the defects capable of generating OSFs and it strongly improves the integrity of 5 nm gate oxides.