Direct evidence of carbon precipitates in GaAs and InP

Abstract

Raman spectra of carbon-doped GaAs and InP show two peaks which are characteristic of C clusters with sp2 bonding. The peaks are seen in C-implanted GaAs and InP following either rapid thermal annealing or furnace annealing. The peaks are also seen in heavily doped epilayers following furnace annealing. Various mechanisms for C precipitation are discussed. Experimental evidence suggests that the loss of the group V component at the surface during annealing may play a role in the precipitation of C.