The difference between 6H-SiC (0001) and (000[formula omitted]) faces observed by AES, LEED and ESCA

Abstract

6H-SiC has a hexagonal structure. The top most surfaces of (0001) and (0001) are only covered with Si and C atoms, respectively. The former is called a Si-rich surface and the latter is called a C-rich surface. These different surface polarities show different surface characteristics. These can also be observed by surface analytical techniques.Here, SiC surfaces were heated to several temperatures (RT-1100°C) for 10 min in an ultra-high vacuum (UHV) chamber. Then the surfaces were observed by LEED (low energy electron diffraction) and AES (Auger electron spectroscopy). The surfaces heated to 1000°C showed the cleanest surfaces. C(KVV)/Si(LVV) AES peak to peak (p-p) height ratio showed a minimum value at 1000°C for all SiC surfaces; on average it is 0.26 on a Si face and 0.38 on a C face. LEED patterns which were heated at 1000°C showed (√3 × √3 - R30°) structure on a Si-rich face and (3 × 3) structure on a C-rich face.After LEED and AES, ESCA experiments were carried out on these samples. C1s/Si2p peak area ratios were 1.2 and 2.0 on Si and C-rich faces, respectively. However, after Ar-ion sputter etching, the differences could not be observed.