Ge concentrations in pile-up layers of sub-100-nm SiGe films for nano-structuring by thermal oxidation
(Color) XRD intensity profiles of the (004) peaks of Si0.8Ge0.2 samples oxidized at various temperatures and times as well as an unoxidized sample. Intensity peaks for the Si substrate, primary SiGe layer, and the pile-up layer are shown. The samples are labeled by oxidation temperature, time, and oxide thickness, while the unoxidized sample is labeled “pre-oxidation.”
(Color online) Ge concentration in the pile-up layer plotted against oxide thickness for samples oxidized at various temperatures and labeled accordingly. Ge concentrations are determined by XRD; oxide thicknesses are determined by ellipsometry. The lines connecting the measured data points are for visual guidance only.
(Color online) Pile-up layer thicknesses of Si0.85Ge0.15 and Si0.8Ge0.2 samples plotted against oxide thickness. The pile-up layer thicknesses are determined by XRD; oxide thicknesses are determined by ellipsometry. Linear fits to the measured data are included to aid in visual interpretation of the data.
(Color online) Ge concentration in the pile-up layer of SiGe samples plotted against oxidation temperature. Data measured by XRD is presented alongside simulation results. The measured data is for samples with initial layers of both 15% and 20% Ge (presented as a single series) while the simulated points are for initial SiGe layers of 20% and 5% Ge and labeled accordingly. Simulated results are presented for three oxide thicknesses and labeled accordingly. The lines connecting the simulated points are for visual guidance only.
(Color online) Ge concentration in the pile-up layer of SiGe samples plotted against oxidation temperature. Data measured by XRD is presented alongside modeled data determined by Eq. (3), using oxide thicknesses determined by ellipsometry. The linear fit to the measured data was used to determine Eq. (1). The coefficients of the activation energy and pre-exponential for the diffusivity of Si in SiGe were determined by matching the linear regressions for the modeled and measured data. The measured and modeled data is for samples with initial layers of both 15% and 20% Ge (presented as a single series.)
(Color online) Oxidation rates for Si and SiGe vs the oxide thickness as measured by ellipsometry. Data from the present work is presented along with simulation results. The simulations used the Massoud (Ref. 7) model and published model parameters (Refs. 6 and 7) with the exception of the linear rate constant, B/A, which was determined from the data from the present work.
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