We demonstrate that the insertion of low-temperature (LT) AIGaN interlayers is effective in reducing mismatch-induced tensile stress and suppressing the formation of cracks during growth of AIGaN dkectly upon GaN epilayers., Stress evolution and relaxation is monitored using an in-situ optical stress sensor.

We report the synthesis and detailed structural characterization of SiGeC metastable alloys formed by solid phase epitaxial regrowth. Epitaxial layers with 0.7 and 1.4 at. % C are formed by 700 °C regrowth of multiple energy carbon implants into preamorphized Si0.86Ge0.14 layers on Si substrates. Transmission electron microscopy and Rutherford backscattering spectrometry show heteroepitaxial regrowth of Si1−x−yGexCy layers into the metastable diamond cubic phase. Fourier transform infrared spectroscopy verifies that the carbon occupies substitutional lattice sites. Double crystal x-ray diffraction measurements of Si1−x−yGexCy and Si1−yCy reference layers quantify the C-induced tensile strain component. This strain compensates for the compressive strain in the SiGe layers, and indicates a change in lattice constant per atomic fraction C in agreement with Vegard’s law.