[20a-E311-1~11] 15.6 Group IV Compound Semiconductors (SiC)

▼ [20a-E311-7] Significant effects on SiO₂/4H-SiC band alignment induced by the difference of employed crystal face and post oxidation annealing processes

〇(D)Taehyeon Kil¹, Koji Kita¹ (1.The Univ. of Tokyo)

Keywords:4H-SiC MOS capacitor, Post-oxidation annealing, Band alignment

In this work, we compared the effect of post-oxidation annealing (POA) on the band alignment shift of Si-face and C-face 4H-SiC. For Si-face, NO-POA, which is well-known method to reduce D_it, is used. For C-face, we focused on the effect of Wet-POA as an annealing method because Wet-POA is already confirmed as an effective method for C-face MOS capacitors. After POA, we estimated conduction band offset (ΔE_c) of each sample by XPS and F-N tunneling current measurements. There was an intrinsic difference of ΔE_c between the Si-face and C-face 4H-SiC MOS interfaces. Moreover, the effect of POA on the band alignment shift also varied according to the crystal face. On Si-face, there was a rise of ΔE_c after NO-POA and increased more with increasing NO-POA duration, whereas the NO-POA and Wet-POA on C-face induced decrease of ΔE_c. Especially after Wet-POA, there was furthermore decrease of ΔE_c, which was the unique effect of Wet-POA on C-face.