J. Zhang et al., IN-SITU MONITORING OF SI AND SIGE GROWTH ON SI(001) SURFACES DURING GAS-SOURCE MOLECULAR-BEAM EPITAXY USING REFLECTANCE ANISOTROPY, Journal of crystal growth, 164(1-4), 1996, pp. 40-46
Reflectance anisotropy (RA) and reflection high energy electron diffra
ction (RHEED) were used simultaneously to study the growth of Si and S
iGe on Si(001) surfaces by gas-source molecular beam epitaxy (GSMBE),
These surfaces are dimerised and have a domain structure created by th
e orthogonal alignment of dimers on terraces separated in height by a(
0)/4. Comparison between the RA and RHEED measurements reveals the ori
gin of dynamic changes in the RA response to be the periodic changes i
n domain coverages on singular surfaces caused by growth under a monol
ayer-by-monolayer mode. It also demonstrates that RA is a more direct
measure of domain coverage variations on the Si(001) surface compared
with RHEED, which may suffer from effects of ordering and multiple sca
ttering, The RA technique is used to investigate domain coverage varia
tions as a function of temperature and following growth interruption.
It is shown that there is no significant change in the domain coverage
at 600 degrees C during growth interruption, consistent with Monte Ca
rlo simulation, This is despite the occurrence of migration of adatoms
/islands as indicated by the recovery of specular beam intensity durin
g simultaneous RHEED measurements, The temperature dependence of the d
ynamic change in RA response is interpreted as a growth mode change at
high temperatures and change in the electronic configuration of the d
imers due to chemisorbed hydrogen at low temperatures. The changes in
the RA response during deposition of SiGe are also investigated as a f
unction of Ge concentration at 600 degrees C growth temperature.