We experimentally studied an impact of the surface oxide layer on quantum confinement effects (QCE) in surfaceoxide/two dimensional (2D)-Si/BOX (buried oxide) quantum well structures (SQW), using UV-Raman spectroscopy, photoluminescence (PL) method, and 2D stress simulator. UV-Raman data show that tensile strain of SQW, stressed by a thermal expansion mismatch between oxide and Si layers, decreases with decreasing the surface oxide thickness TOX. According to the strain behavior in SQW and strained-Si, PL results show that bandgap EG of the SQW rapidly expands with decreasing TOX. However, QCE in SQW keep stable in spite of high temperature postannealing process.
Contact property of aluminum and 4H-SiC wafer with crystallized amorphous-silicon (a-Si) interlayer was investigated. A phosphorus-doped a-Si layer on SiC wafer was crystallized by annealing at 1377 °C. Good ohmic contact behavior and contact resistivity of 2.1 × 10-6Ωcm2were obtained without silicidation annealing process. Furthermore, non-doped crystallized a-Si layer insertion layer also showed ohmic contact property. However, high contact resistivity of 8.2×10-4Ωcm2was obtained in the non-doped a-Si sample. X-ray photo-electron spectroscopy analysis suggests that conduction band offset is significantly reduced between crystallized a-Si and SiC wafer. Therefore, a-Si insertion layer is effective for Schottky barrier height decreasing and high doping into Si layer forms low contact resistivity between Al and SiC, indirectly.
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