Behaviour of RHEED Oscillation during LT-GaAs Growth
Hungarian Academy of Sciences, Research Institute for Technical Physics and Materials Science, P.O.Box 49, H-1525 Budapest, Hungary, firstname.lastname@example.org
The behaviour of RHEED oscillations during MBE growth on GaAs (001) surface under low temperature (LT) growth conditions is examined in this work. The RHEED and its intensity oscillations of LT-GaAs growth have some particular behaviour. The intensity, phase and decay of oscillations depend on the beam equivalent pressure (BEP) ratio and substrate temperature etc. We examine here the intensity dependence of RHEED behaviour on BEP ratio, substrate temperature and the excess of As content and the lattice mismatch in the layer.
Recently, MBE growth of GaAs at LT - around 200 C - has an increasingly importance in the semiconductor research and technology. The LT-GaAs growth has become an expanding important method since it provides highly insulating films and contributes to the synthesis of magnetic semiconductors. It was shown that growth at this LT leads to incorporation of excess As in the crystal. The high concentration of excess As in LT-GaAs results in a number of novel properties. The RHEED oscillations are very strongly influenced by the growth parameters, such as deposition temperature, ratio of BEP etc. The RHEED oscillations were found fundamental in two regions of BEP ratio at LT.
The decay and absence of the RHEED intensity oscillations can origin from several effects e.g. change of sticikng coefficients, change of unperturbed area and change of strain. Here was found, that the separation of growth and strain influence on the RHEED oscillation decay in the case of LT-GaAs is possible in a narrow region of BEP ratio. The functions of lattice spacing vs BEP ratio are determined, too.
This work was supported by the Hungarian Scientific Research Fund (OTKA) through Grant No. T037509, which is very acknowledged.