Growth and electron effective mass measurements of strained Si and Si0.94Ge0.06 on relaxed Si0.62Ge0.38 buffers grown by rapid thermal chemical vapor deposition
Journal
Materials Chemistry and Physics
Journal Volume
49
Journal Issue
1
Pages
29-32
Date Issued
1997
Author(s)
Abstract
We report the growth and the electron cyclotron resonance measurements of n-type Si/Si0.62Ge0.38 and Si0.94Ge0.06Si0.62Ge0.38 modulation-doped heterostructures grown by rapid thermal chemical vapor deposition. The strained Si and Si0.94Ge0.06 channels were grown on relaxed Si0.62Ge0.38 buffer layers, which consist of 0.6 μm uniform Si0.62Ge0.38 layers and 0.5 μm compositionally graded relaxed SiGe layers from 0 to 38% Ge. The buffer layers were annealed at 800°C for 1 h to obtain complete relaxation. A 75 Å Si(SiGe) channel with a 100 Å spacer and a 300 Å 2×1019 cm-3 n-type supply layer was grown on the top of the buffer layers. The cross-sectional transmission electron microscope reveals that the dense dislocation network is confined to the buffer layer, and relatively few dislocations terminate on the surface. The planview image indicates the threading dislocation density is about 4×106 cm-2. The far-infrared measurements of electron cyclotron resonance were performed at 4 K with the magnetic field of 4-8 T. The effective masses determined from the slope of the center frequency of the absorption peak versus applied magnetic field plot are 0.203m0 and 0.193m0 for the two dimensional electron gases in the Si and Si0.94Ge0.06 channels, respectively. The Si effective mass is very close to that of a two dimensional electron gas in an Si MOSFET (0.19Sm0). The electron effective mass of Si0.94Ge0.06 is reported for the first time and is about 5% lower than that of pure Si.
Type
journal article