[20p-D103-1~14] 15.6 Group IV Compound Semiconductors (SiC)

▼ [20p-D103-8] Thermal-oxidation-induced lattice distortion at 4H-SiC (0001) surface and its recovery by Ar annealing

〇Adhi Dwi Hatmanto¹, Koji Kita¹ (1.Dept. of Materials Engineering, The Univ. of Tokyo)

Keywords:4H-SiC (0001), lattice distortion, in-plane X-ray diffractometry

Local lattice distortions at the surface of 4H-SiC(0001) after various thermal oxidation processes were investigated by in-plane X-ray diffractometry. Our results showed that dry oxidation induced lattice distortion, observed as the increase of d(1-100) interplanar spacing, became higher with increasing oxidation time. Lattice constant changes of up to around 0.4% were observed by increasing the oxide thickness to 44 nm. This lattice distortion was not recovered after removal of the SiO₂ layer by chemical etching. However, it was partially reduced by post-oxidation Ar gas annealing at high temperature, suggesting that strain relaxation requires removal of oxidation-induced defects in the 4H-SiC surface region. This Ar annealing-induced lattice distortion recovery was larger for longer annealing time. Furthermore, we examined the lattice distortion at the surface of NO-annealed sample and found that the impact of NO annealing on the lattice distortion recovery was almost the same as Ar annealing. Our results revealed that oxidation and annealing processes should have a significant impact on the quality of the 4H-SiC surface.