Adsorption of TiCI₄on TiSi₂: Application to Silicide Chemical Vapor Deposition

Low pressure chemical vapor deposition of InSb using neo-pentylstibine and trimethylindium has been studied with x-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy, Raman spectroscopy, and scanning electron microscopy (SEM). At 600 K, the InSb film with an In:Sb atomic ratio of 1 and a growth rate of —2 A/min was formed on GaAs(llO). The binding energies of the In and Sb 3 d_5/2XPS peaks are in excellent agreement with those taken from InSb single crystal and amorphous samples. The He(II) ultraviolet photoelectron spectrum also agrees reasonably well with photoemission spectra taken from InSb using different photon beam sources. The corresponding Raman spectrum showed two phonon peaks at 179 (TO) and 190 (LO) cm^-1, respectively, which are virtually identical to the Raman data reported for InSb single crystal samples. The XPS measurements suggested a three-dimensional growth mechanism for the InSb film on GaAs(l 10), which was confirmed by the SEM measurement. However, at —800 A thickness, the SEM picture showed a very smooth InSb film, with the presence of some uncovered holes corresponding to —3% of the total surface area. The substrate temperature effect on the film growth was also investigated. At temperatures below 400 K, film growth was very slow and the decomposition of NpSbH₂and TMIn seemed to be incomplete, whereas above 800 K, metal droplets were clearly visible by SEM. The optimal growth temperature lies at approximately 600–700 K.