[11p-N305-1~10] 13.7 Compound and power devices, process technology and characterization

▲ [11p-N305-6] Evaluation of long-term reliability of 4H-SiC(0001) CMOS ring oscillators at high temperature

〇(PC)Kidist Moges Ayele¹, Takuma Kobayashi¹, Takuji Hosoi¹, Takayoshi Shimura¹, Keita Tachiki², Tsunenobu Kimoto², Heiji Watanabe¹ (1.Graduate School of Eng., Osaka Univ., 2.Graduate School of Eng., Kyoto Univ.)

Keywords:SiC CMOS, Long-term reliability, High-temperature reliability

We evaluated the long-term reliability of 4H-SiC(0001) CMOS ring oscillators (ROs) fabricated by ultrahigh temperature gate oxidation at 1600°C in a reduced O₂/Ar ambient pressure of 0.3 kPa (HTO). Furthermore, ROs were fabricated by subsequently performing forming gas annealing at 1200°C (FGA). The reliability test was conducted by applying bias stress at 200°C and allowing the ROs to continuously operate for 1hr. Unlike the reference ROs fabricated by the standard post-oxidation annealing in NO ambient (NO−POA), HTO and FGA ROs showed only a small shift after 1hr of operation. These results indicate the improvement of the long-term reliability by HTO and FGA gate oxidation processes in comparison with that of NO−POA.