HYDROGEN PLASMA PROCESSING OF GAAS AND ALGAAS

Hydrogen plasma processing of GaAs and AlGaAs using an electron cyclot ron resonance plasma reactor, which is vacuum-linked to a molecular-be am epitaxial (MBE) growth chamber is reported. Native oxide removal an d surface cleaning of GaAs is characterized using hydrogen plasma proc essing, subsequent thermal Cl2 etching, and vacuum annealing. It is sh own that surface reconstruction and excellent GaAs/GaAs interfaces can be achieved using these dry vacuum procedures. It is also shown that AlxGa1-xAs native oxides can be removed for 0 less-than-or-equal-to x less-than-or-equal-to 1 using hydrogen plasma processing before MBE ov ergrowth. The best AlGaAs/AlGaAs interfaces are obtained using low mic rowave power during hydrogen plasma processing. 0 and C impurities det ected at these interfaces increase with higher Al composition; Si inte rface impurities tend to increase with higher microwave power. In gene ral, hydrogen plasma processing is judged effective for surface prepar ation before MBE growth for the complete range of AlGaAs alloys.