Crystalline quality of strain-free GaAs-on-Si structures formed by annealing under ultrahigh pressure

Crystalline quality and residual strain in GaAs films epitaxially grown on Si substrates have been investigated after annealing them under ultrahigh pressures up to 2.1 GPa. The strain in the films decreased linearly with increase of pressure and it became zero at a pressure around 1.9 GPa. The strain depended weakly on the annealing temperature in the range from 300 to 500 °C. A slight increase in the channeling minimum yield in Rutherford backscattering spectrometry was observed in the samples with broad-area GaAs films. However, the degradation in the crystalline quality was avoided by etching the GaAs films in a stripe pattern with 10 μm width.