Investigation of Al-implanted 6H-and 4H-SiC layers after fast heating rate annealings
Résumé
6H- and 4H-SiC n-type layers were amorphised by multiple Al implantations at room temperature, in order to study the annealing process. This paper deals with the influence of specific annealing conditions, such as furnace atmosphere and heating rate, on SiC reordering and Al profile. Below a certain deposited nuclear energy, solid phase epitaxy (SPE) is possible and leads to recrystallisation under precise conditions (high heating rate, silicon partial pressure prescribed). Above that, partial reordering is only observed for 4H-SiC layers, and leads to some increasing roughness, even though annealing has proven to be efficient for avoiding surface impairment (due to a specific cleaning process). Some Al oscillations have been observed near the junction in case of SPE, whereas a flat homogeneous profile is formed in amorphised layers. (C) 2001 Elsevier Science B.V. All rights reserved.