A study was made of (100) crystals, oriented 9º off-axis towards , which had been exposed to 2Torr of tertiarybutylarsine and 99Torr of H at 650C and then heated to between 450 and 600C in vacuum or H2. The resultant surfaces consisted of narrow dimer-terminated terraces, with (1 x 2) and (2 x 1) domains that were separated by steps of between 1 and 8 atomic layers in height. The distribution of (1 x 2) and (2 x 1) domains changed with temperature, and exhibited a pronounced maximum in the (1 x 2) fraction at 510C. The results suggested that As passivation of Ge was a critical step in GaAs hetero-epitaxy.
Step structure of arsenic-terminated vicinal Ge(100) S.Gan, L.Li, M.J.Begarney, D.Law, B.K.Han, R.F.Hicks: Journal of Applied Physics, 1999, 85, 2004-6