M. Kuball et al., The use of micro-Raman spectroscopy to monitor high-pressure high-temperature annealing of ion-implanted GaN films, MRS I J N S, 5, 2000, pp. NIL_635-NIL_640
We have investigated the high-pressure high-temperature annealing of Mg/P-i
mplanted GaN films using visible and ultraviolet (UV) micro-Raman spectrosc
opy. The results illustrate the use of Raman spectroscopy to monitor proces
sing of GaN where fast feedback is required. The structural quality and the
stress in ion-implanted GaN films was monitored in a 40nm-thin surface lay
er of the sample as well as averaged over the sample layer thickness. We fi
nd the nearly full recovery of the crystalline quality of ion-implanted GaN
films after annealing at 1400-1500 degreesC under nitrogen overpressures o
f 1.5GPa. No significant degradation effects occurred in the GaN surface la
yer during the annealing. The high nitrogen overpressures proved very effec
tive in preventing the nitrogen out-diffusion from the GaN surface. Stress
introduced during the annealing was monitored. Raman spectra of ion-implant
ed GaN films were investigated at different temperatures and excitation wav
elengths to study the GaN phonon density of states.