CF4/O-2 PLASMA INDUCED DAMAGE IN SI-IMPLANTED N-TYPE GAAS CRYSTALS

摘要

The CF4/O-2 Or CF4 plasma induced damage in Si-implanted It-type GaAs crystals has been investigated by using Hall measurement and secondary ion mass spectrometry (SIMS) analysis. We found that sheet resistance degraded after plasma exposure and postannealing. The degradation of the sheet resistance during postannealing at 200-400 degrees C, is mainly associated with the reduction of carrier density in the crystal. From SIMS analysis, fluorine contamination was observed in the surface region of GaAs crystals after CF4/O-2 plasma exposure. The internal diffusion of fluorine atoms and the localization of fluorine in the Si-implanted a-type GaAs layer, were observed after postannealing at 400 degrees C. Based on these findings, a fluorine passivation related model is proposed, where Si-F bonds are formed in the Si-implanted a-type GaAs crystals. (C) 1997 American Institute of Physics. References: 10