Strain State and Thermal Stability of Strained-Si-on-Insulator Substrates

The strain state and thermal stability of strained-Si-on-insulator (sSOI) substrates fabricated by the Smart Cut® technique were precisely analyzed by X-ray diffraction reciprocal space mapping and Raman spectroscopy. It was demonstrated that the strain was well maintained even after annealing at temperatures up to 1120 °C in spite of the thickness being larger than the critical thickness. The strain reduction of only 10% was observed at 1150 °C, but the surface smoothness with the RMS roughness below 0.2 nm and high crystal quality did not change. This indicates the high applicability of sSOI to the current Si processes.