Characterization of the nitrided GaAs thin layers after rapid thermal annealing by using raman scattering

Abstract

By using Raman spectroscopy, we examine defects generated from the nitridation of a GaAs surface performed by a nitrogen electron cyclotron resonance (ECR) plasma at various temperatures and its changed properties after the isochronal (15sec) rapid thermal annealing (RTA) at 750°C, 850°C and 950°C. The unpolarized Raman spectra taken from the nitrided samples show that the bandwidths and the peak frequencies for LO phonon band were broader and downshifted due to result from the increased nitridation temperature, respectively, but the spectra obtained after RTA are inclined to recover to the bandwidth and the peak frequencies of the un-nitrided sample. And the height ratio of TO/LO is also decreased. We estimate the correlation length for each sample from the relationship between the Raman shift of LO phonon and the broadening as a function of correlation length, and show that the point defects can be annealed out by annealing processes. ？ 1998 Institute of Electrical and Electronics Engineers Inc.. All rights reserved.