[20p-H101-1~21] 15.6 Group IV Compound Semiconductors (SiC)

▼ [20p-H101-12] Thermal oxidation enhancement using barium on 4H-SiC(0001) substrates

〇(PC)Atthawut Chanthaphan¹, Yoshihito Katsu¹, Takuji Hosoi¹, Takayoshi Shimura¹, Heiji Watanabe¹ (1.Osaka Univ.)

Keywords:SiC,oxidation,barium

We investigated the effect of barium (Ba), a heavy alkaline earth element on metal enhanced oxidation (MEO) on 4H-SiC(0001). The thin Ba layers were deposited on the SiC surfaces with subsequent MEO in pure ambient O₂ gas at 950°C. We found that the oxidation rate of 4H-SiC(0001) remarkably enhanced using Ba layers. The MEO rate using Ba at 950°C was higher than the standard oxidation rate for bare 4H-SiC at 1150°C. In addition, the locations of Ba atoms before and after MEO were examined by x-ray photoelectron spectroscopy (XPS). It was found that most of Ba atoms were located at the SiO₂ surface after MEO but still effective in enhancing oxidation rate. A large amount of Ba atoms can be removed from the oxides by partial etching in 1% HF. Lastly, we also fabricated the SiC-MOS capacitors containing Ba atoms in the oxides to observe bias-temperature instability (BTI). Since small clockwise capacitance-voltage (C-V) characteristics due to electron injection were observed at both room and high temperatures, Ba atom does not act as a mobile ion in SiC-MOS devices.