GAAS EPITAXY BY CHEMICAL-VAPOR TRANSPORT UNDER HIGH, EARTH AND LOW-GRAVITY CONDITIONS

Homoepitaxy of GaAs on hemispherical substrates have been realised by chemical vapour transport in four different gravity levels. Experiment s have been performed on earth, under 5g and 10g acceleration conditio ns using a centrifuge and under a microgravity environment (EURECA-I m ission). The source was either undoped GaAs or tin-doped GaAs. Analysi s and comparison of the grown layers show that, in the applied conditi ons, the gravity level is not a relevant parameter and that tin is an inhibitor for the GaAs epitaxy.