Solid phase epitaxy of implantation-induced amorphous layer in (11̄00)- and (112̄0)-oriented 6H-SiC

Abstract

The epitaxial regrowth of the implantation-induced amorphous layer in (11̄00)- and (112̄0)-oriented 6H-SiC has been investigated at annealing temperatures below 800 °C using Rutherford backscattering spectrometry and transmission electron microscopy. The surface region of sample is amorphized by the Ar+ ion implantation with an energy of 100 keV at a dose of 2×1015/cm2. The implantation-induced amorphous layer epitaxially regrows at annealing temperatures above 700 °C without the inclusion of other polytype crystals such as 3C-SiC and twinned defects. The regrowth rate is estimated to be about 0.4 nm/min at 700 °C and is proportional to the annealing temperature with an activation energy of about 3.4 eV for both (11̄00)- and (112̄0)-oriented 6H-SiC.

Atomic-level simulations of epitaxial recrystallization and amorphous-to-crystalline transition in4H−SiC

“…Further epitaxial regrowth is impeded by the nucleation and grain growth of these secondary phases, which leads to a slower reduction of amorphous fraction at 2000 K. However, the behavior of amorphous fraction at 2000 K in the M x model is different from that in the M y model, with a much faster recovery rate, which is consistent with experimental observations in 6H-SiC. 35 The nucleation of secondary ordered phases in the M x model is also observed, but appears only after significant recrystallization has occurred, where the size of the amorphous region is much smaller than that of the original amorphous region. On the other hand, the nucleation of secondary ordered phases in the M y model appears at a very early stage, where the size of the amorphous region is similar to that of the original amorphous region.…”

“…Complete recrystallization is reached after about 210 ns at 2000 K. However, it is clear that the formation of secondary ordered phase at the interfaces hinders the SPEG process in 4H-SiC, which may suggest that much higher temperatures are required to completely recover the 4H structure along the ͓0110͔ crystallographic direction than the ͓1210͔ direction. This has been observed experimentally by Satoh et al 35 in 6H-SiC, where the regrowth rate of implantation-induced amorphous layer is faster for ͑1210͒-orientated sample than that for ͑0110͒-orientated sample, or a higher temperature is needed for ͑0110͒-orientated sample to achieve the same regrowth rate. In comparison with the annealing simulations of the M x model ͑Fig.…”

“…42 However, a much higher value of 3.4 eV has been reported for 6H-SiC under other crystallographic orientations. 35 This clearly indicates that the different atomic stacking sequence at the a-c interfaces may have significant effects on the recrystallization mechanisms.…”

“…34͒ and 6H-SiC. 35 Zhang et al 10 studied the effects of implantation temperature and ion flux on damage accumulation under Al ion irradiation in 4H-SiC, and the amorphous sample was annealed at a temperature of 450 K. The results suggest that planar defects are generated through the agglomeration of excess Si and C interstitials during postirradiation annealing, and some vacancy clusters are also observed. Solid phase epitaxy of implantation-induced amorphous layer in ͑1210͒-oriented 6H-SiC ͑Ref.…”

“…10,12,14,34,35,38 Most of the recrystallization studies have been carried out in 6H-SiC ͑Refs. 10, 12, 14, and 38͒ along ͗0001͘ direction.…”