Competition between Oxidation and Recrystallization in Ion Amorphized (0001) 6H-SiC

Abstract

The wet oxidation of (0001), Si-face, 6H-SiC pre-amorphised by Ar+ implantation has been investigated in the temperature range between 750 and 950 °C. Electron microscopy analysis has been performed to obtain information on the evolution of the amorphous layer during the oxidation process. When the oxidation occurs on the amorphous substrate the observed rate is given by VOx(a)=3.8x107exp(-1.6eV/kT) nm/min, by far faster than that observed on single or polycrystalline 6H-SiC. For amorphous layer thickness of a few hundreds nanometer and processing time of a few tens of minutes this happens up to oxidation temperatures of about 910 °C, owing to the concomitant recrystallization process. At higher temperature, our oxidation data support the existence of a sudden variation of the recrystallization process that rapidly reduces the residual amorphous region and, consequently, the oxide thickness. However, it appears that this second recrystallization stage is faster than previously estimated. Structural detail of the starting amorphous-crystalline interface and of the early-recrystallized layers are reported and discussed.