Angular distortion of Si clusters in a-SiC

¹ Dipartimento di Fisica e Astronomia - Corso Italia 57, I-95129 Catania, Italy
² INFM - Corso Perrone 24, I-16152 Genova, Italy

Corresponding author: riccardo.reitano@ct.infn.it

Received: 14 March 2001
Accepted: 22 June 2001

Abstract

In this letter we report on the unusually large bond angle distortion of silicon clusters in an amorphous silicon carbide matrix. The samples, produced by Ar⁺ ion irradiation of single crystal 6H-SiC, have been analyzed by Raman spectroscopy. The apperance of both Si-Si and C-C related bands points to the formation of silicon and carbon clusters in the amorphous SiC matrix. The width of the Si-Si Raman band was found to be almost twice that of ion-implanted amorphous silicon. In terms of root-mean-square bond angle distortion, we found a value of . Upon annealing, increases up to at 700 C, while in amorphous silicon it decreases from to . It is the relaxation of the a-SiC matrix that provides the energy required to increase the distortion of the silicon clusters. Taking into account the variation of the number of clusters with annealing, the total energy stored in the distortion of the clusters decreases from 20 kJ/mole to 10 kJ/mole.