An RDS, LEED, and STM Study of MOCVD-Prepared Si(1 0 0) surfaces

Abstract

Clean, As- and P-terminated Si(1 0 0) surfaces were prepared with H 2 carrier gas and AsH 3 and PH 3 as precursors in an MOCVD chamber. Reflectance difference spectra (RDS) were taken in situ. Samples were then transferred under vacuum to an ultrahigh-vacuum (UHV) chamber for analysis with AES, LEED, and STM. Clean, As-terminated Si(1 0 0) surfaces were achieved by annealing the sample at T<900 °C supplying either AsH 3 or hydrogen (plus background As x ). Various preparation procedures were applied and benchmarked in UHV. Extended annealing under AsH 3 led to strongly faceted surfaces whereas AsH 3 flow of moderate concentration, temperature, and time led to flat, two-domain, (2×1)/(1×2) reconstructed surfaces. RD spectra almost identical to RD spectra of As/Si(1 0 0) surfaces prepared in UHV with MBE were obtained by annealing the samples under AsH 3. Annealing under PH 3 supply bore a new, two-domain (6×3)/(3×6) surface reconstruction at low flows, and a SiP compound at high flows.