AVS 45th International Symposium
    Electronic Materials and Processing Division Friday Sessions
       Session EM-FrM

Paper EM-FrM9
Carbon Incorporation in SiGeC Alloys Grown by UHV/CVD

Friday, November 6, 1998, 11:00 am, Room 316

Session: Fabrication and Characterization of Semiconductor Device Layers
Presenter: A.C. Mocuta, Carnegie Mellon University
Authors: A.C. Mocuta, Carnegie Mellon University
D.W. Greve, Carnegie Mellon University
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We report on growth and carbon incorporation in Si@sub1-x-y@Ge@sub x@C@sub y@ alloys with up to 2% carbon concentration grown by Ultrahigh Vacuum Chemical Vapor Deposition using silane, germane and methylsilane as Si, Ge and C precursors. Alloy growths have been performed at temperatures ranging from 550 °C to 650 °C. Carbon incorporation has been studied for alloys with Ge content of about 5%, 10% and 20%. The Si@sub1-x-y@Ge@sub x@C@sub y@ layers grown on Si(100) substrates have been analyzed by High Resolution X-ray Diffraction (HRXRD) and Secondary Ion Mass Spectrometry (SIMS). For low methylsilane flow and growth temperature of less than 600 °C carbon is incorporated on substitutional positions in levels of up to 0.3%. With increasing methylsilane flow carbon begins to occupy interstitial positions as well but also, the germanium fraction in the layer begins to increase. For carbon concentrations of 1% or higher the crystal quality of the alloy is degraded. Thermal stability and critical thickness for layers with about 10% Ge and low carbon levels (0.2%) has also been studied. Addition of small amounts of carbon to SiGe layers greatly improves the thermal stability of the layer. Upon annealing for 1 hour at 900 °C no significant strain relaxation occurs in Si@sub1-x-y@Ge@sub x@C@sub y@ single layers or multiple quantum well structures while in similar SiGe structures with comparable strain and thickness strain relaxation is observed.