RAMAN-SCATTERING STUDY OF THE RECOVERY PROCESS IN GA ION-IMPLANTED GASB

Recovery process in GaSb crystals with Ga ion implantation and subsequ ent annealing by rapid thermal annealing (RTA) or furnace annealing (F A) methods are studied by Raman scattering. The intensity of the GaSb LO phonon mode decreases with increasing ion implantation fluence. It is found that the threshold fluence to the amorphization for the Ga io n implanted GaSb is 5 X 10(13) cm-2. It is much lower than that for In P (1 X 10(14) cm-2). In the face-to-face FA, the recovery processes in the Ga ion implanted GaSb are very different above and below the flue nce of 5 X 10(14) cm-2. For the 5 X 10(14) cm-2 Ga ion implantation, n o recovery is observed. Below 5 X 10(14) cm-2 implantation, the GaSb L O mode intensity increases with increasing annealing temperature and w ith time up to 400-degrees-C and 15 min, respectively. However, the re covery of damage is very poor compared with that of GaAs, InP, and GaP . On the other hand, in the Si3N4 caped RTA the recovery is observed e ven for the 5 X 10(14) cm-2 implantation. New modes are observed at ar ound 114 and 150 cm-1 in the implanted and annealed GaSb samples. Thes e two modes are related to E(g) and A1g modes of Sb-Sb bond vibrations , respectively, and are produced due to the out diffusion of Sb atoms. It is found that the face-to-face annealing enhances the outdiffusion of Sb, and that the Si3N4 caped RTA process is superior to the face-t o-face FA process for the healing of the damaged layers. These anomalo us behaviors are closely related to the weak bond strength of Sb conta ining materials. The degree of the recovery as a function of annealing temperature, annealing time, and ion implantation fluence is also inv estigated in both RTA and FA methods.