AVS 49th International Symposium
    Electronic Materials and Devices Wednesday Sessions
       Session EL+SS+SC-WeA

Paper EL+SS+SC-WeA7
Reactions of Organosulfur Compounds with Si(100) for Chemically Controlled Epitaxy of II-VI Semiconductors on Si(100)

Wednesday, November 6, 2002, 4:00 pm, Room C-107

Session: Semiconductor Film Growth and Oxidation
Presenter: R.M. Osgood Jr., Columbia University
Authors: Z. Zhu, Columbia University
A. Srivastava, Columbia University
R.M. Osgood Jr., Columbia University
Correspondent: Click to Email
The growth of silicon-based quantum devices requires precise control of ultrathin Si/wide-bandgap-semiconductor/Si heterostructures. We have investigated the initial stages of chemistry-based low-temperature epitaxy using organosulfur precursors. The approach uses the chemical insight gained from organic functionalization of Si.@footnote 1@ Thus we have studied the reaction of (CH@sub 3@S)@sub 2@, CH@sub 3@SH, (CH@sub 3@)@sub 2@S with Si(100) at room temperature, under UHV conditions for atomic layer growth of functional-group-terminated sulfur on Si(100). This reaction is the first step in the layer by layer self-limiting epitaxy of ZnS, for example, on Si(100). AES studies indicate that each of these organosulfur compounds have different reaction kinetics with the Si(100) surface and reach different levels of sulfur saturation coverage. The differences observed for (CH@sub 3@S)@sub 2@ and (CH@sub 3@)@sub 2@S reactions have been shown to be explained by the relative bond strengths and the number of sulfur atoms present in the adsorbate molecule. Our TPD studies from 25-825°C show no sulfur-related desorption. Instead AES studies confirm that sulfur atoms remain on surface until ~ 525°C and then diffuse into the Si(100) substrate upon further annealing. TPD studies also indicate evolution of H@sub 2@ at temperatures similar to those obtained for H@sub 2@ desorption from saturated atomic H on Si(100). In our studies methyl desorption also occur at T > 650° C, temperatures higher than that of H@sub 2@ desorption. The amount of m/e = 15,16 fragments is dependent on the organosulfur compound examined. Chemical strategies are now being explored to grow layers of Zn on methyl-terminated sulfur layer as shown in the epitaxy using sequential H@sub 2@S/dimethyl cadmium dosing on ZnSe.@footnote 2@ @FootnoteText@ @footnote 1@Bent SF, J Phys Chem B, 106(11): 2830-2842, 2002. @footnote 2@Luo Y, Han M, Slater DA, Osgood RM, J Vac Sci Tecnol A 18(2): 438-449, 2000.