Real-time investigations of GaAs surface cleaning with a hydrogen electron cyclotron resonance plasma by optical reflection spectroscopy

Abstract

The composition changes during GaAs oxide removal and the subsequent cleaning with a hydrogen electron cyclotron resonance plasma have been investigated with real-time optical reflection spectroscopy. It is found that the oxide is not completely removed at low temperatures, resulting in a thick damaged surface region. At moderate temperatures (300–500 °C) the plasma exposure is characterized by a two-step process: a removal of the native oxide in a few seconds followed by a gentle etch of the GaAs. In the latter step the plasma exposure leads to a surface region with little damage to the crystal.