Sulphur-terminated silicon surfaces for the epitaxial growth of chalcopyrite semiconductors

As an alternative to wet chemical treatments and hydrogen termination, we p ropose the sulphur-termination of silicon surfaces in order to obtain favou rable starting conditions for epitaxial growth of chalcopyrite semiconducto rs. We show that a high-temperature treatment of Si(0 0 1) and Si(1 1 1) in ultra-high vacuum under continuous exposure to a reactive sulphur molecula r beam from a cracker source leads to new well-defined ordered surfaces. We identify the ideal sulphur termination of Si(0 0 1) with (1 x 1) structure and a quasi-ideal termination of Si(1 1 1) with a (4 x 4) surface structur e. We propose structural models and discuss three surfaces also in the ligh t of former experimental effort and theoretical predictions. Furthermore, w e elucidate the implications of sulphur termination for epitaxial growth of the CIS compound. (C) 2001 Elsevier Science B.V. All rights reserved.