A COMPARISON OF ATOMIC CARBON VERSUS BERYLLIUM ACCEPTOR DOPING IN GAAS GROWN BY MOLECULAR-BEAM EPITAXY

Atomic carbon doping by solid-source molecular beam epitaxy (MBE) using a resistively heated graphite filament is investigated. Reproducible doping levels up to 10(20) cm-3 are obtained with good hole mobilities. Results concerning the high limit of bulk doping and delta-doping with carbon are presented. A systematic variation of the V/III ratio showed no evidence of an amphoteric behavior of carbon. Comparison with beryllium doped layers grown in the same MBE system shows similar optical quality for the low doping range and degradation for carbon doping only above 10(19) cm-3. Carbon memory effects are found to be negligible after the growth of thin doped layers. These results show that carbon could replace advantageously beryllium in most electronic and optical devices.