Crystallization and surface erosion of SiC by ion irradiation at elevated temperatures

The effects of high dose ion irradiation through amorphous surface layers o n single crystalline 6H-SiC at elevated temperatures are studied in detail. Material swelling, subsequent densification, and surface erosion are quant ified for irradiation at 500 degrees C. Ion beam induced recrystallization is investigated in the temperature range between 300 and 1300 degrees C. Th e results demonstrate that undisturbed epitaxial regrowth of an amorphous s urface layer in(0001)-oriented 6H-SiC cannot be achieved by ion irradiation . The shift of the amorphous/crystalline interface observed by Rutherford b ackscattering spectrometry/channeling analysis is a consequence of columnar growth and surface erosion. The columnar growth starts inside the heavily damaged transition region between the amorphous surface layer and the singl e crystalline bulk material. It is stopped by random nucleation which is st rongly enhanced by ion irradiation in the temperature range between 300 and 1000 degrees C. Neither the interface roughness nor the kind of impurity a toms influence the thickness of the columnar layer. At higher temperatures, the interface shift is dominated by thermal regrowth and ion beam enhanced surface erosion. (C) 1999 American Institute of Physics. [S0021-8979(99)02 403-2].