L Journal of Alloys and Compounds 286 (1999) 143–147 XPS and XRD study of crystalline 3C-SiC grown by sublimation method a, a a b * R.J. Iwanowski , K. Fronc , W. Paszkowicz , M. Heinonen a Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32 /46, 02-668 Warsaw, Poland b Materials Science Laboratory, Department of Applied Physics, University of Turku, Vesilinnantie 5, 20014 Turku, Finland Abstract Preliminary XPS and XRD studies of the 3C-SiC polycrystals (with the grain size of order of 100 mm) grown by the sublimation method were performed. The XRD data proved a dominant 3C-SiC structure accompanied by an admixture of the residual 6H-SiC phase. The main core-level photoelectron spectra were analysed in detail. In particular, the C 1s level spectrum revealed a three peaks structure a containing the peak indicative of free carbon as well as the remaining two identified as the carbidic components, centered at E 5282.3 eV B b and E 5283.4 eV. The fact, that the most intensive peak ‘a’ was found especially well resolvable in the acquired spectrum (as not B observed in the earlier reports) was linked with a dominance of 3C-SiC phase and a relatively high lattice perfection of the crystals studied. Therefore, it enabled us a reliable identification of the main C 1s line component (peak ‘a’) as related to the C-Si bond in cubic Si C crystal with slight deviation from stoichiometry (0.5,xu0.54). On the other hand, the minor carbidic component (peak ‘b’) was 12x x ascribed to the C-Si bond in the highly C-saturated cubic Si C ( x.0.6) compound that is present in the surface region.  1999 12x x Elsevier Science S.A. All rights reserved. Keywords: X-ray photoelectron spectroscopy; X-ray diffraction; Silicon carbide; Surface studies 1. Introduction (XPS) studies of SiC, although not vast, concerns mainly its most common polytype, i.e. the hexagonal 6H-SiC (see Growing interest in silicon carbide, observed during past the representative set of references [3–5]). The polytypism two decades, has arisen from the need for electronic of SiC makes it nontrivial to grow a single-phase crystal of devices capable to operate at high power levels, high high lattice perfection [1], especially in a 3C-SiC form temperatures and hostile environments, as well as from the [6–8]. Up to now, the most systematic XPS and X-ray need for optical materials which are active in the blue diffraction (XRD) studies of polycrystalline (thick film) wavelengths. 3C-SiC was reported in [7]. SiC is a wide-gap semiconductor, where the large Si-C Recent progress in a growth of the single phase crys- bonding energy provides its enhanced resistance to chemi- talline 3C-SiC, achieved at the Institute of Physics Polish cal attack and ensures high temperature stability-it is also Academy of Sciences [9], have motivated us to perform characterized by large breakdown fields (see [1] and preliminary XPS and XRD measurements of the cubic references therein). Silicon carbide exists in numerous silicon carbide. polytype forms, which can be distinguished by the stacking sequence of the tetrahedrally bonded Si-C bilayers, such that the individual bond lengths and local atomic environ- 2. Experiment ments are nearly identical, while the overall symmetry is determined by the stacking periodicity [1,2]. Among the The cubic SiC samples were grown in an electron heated polytypes of SiC, cubic silicon carbide (3C-SiC or b-SiC) graphite crucible by synthesis from high purity silicon and with the energy gap E (300 K)52.2 eV and relatively high graphite powder followed by sublimation (at 19008C) in o electron mobility appears as a promising and perspective the high vacuum conditions. Typical specimen had a form material for the above mentioned applications [1]. of yellow large-grain (with the size below 0.5 mm) The bibliography on X-ray photoelectron spectroscopy polycrystals grown on the graphite substrate. X-ray measurements were done using an automated Bragg-Brentano diffractometer of radius equal 29.1 cm in a *Corresponding author. E-mail address: iwano@ifpan.edu.pl. (R.J. Iwanowski) step-scanning mode. Scanning step size was 0.028. The 0925-8388 / 99 / $ – see front matter  1999 Elsevier Science S.A. All rights reserved. PII: S0925-8388(98)00994-3