Pressure-Induced Phase Transformations In Semiconductors Under Contact Loading

Abstract

A combination of indentation testing and Raman microspectroscopy was used to study phase transformations in semiconductors under contact loading. Metastable high-pressure phases were observed in the nanoindents on Si and Ge, suggesting indentation-induced transformation to a metallic phase. GaAs was shown to deform by plastic flow at room temperature. The peculiarities in the indentation load-displacement behavior of Si (“pop-out” events) were assigned to a phase transformation upon pressure release. Raman imaging was successfully used to visualize phase distributions and stress fields around the hardness imprints on Si. Possible applications of the proposed technique are in the area of mechanical surface nanomachining of semiconductors, and selective 2D surface patterning with amorphous material or metastable high-pressure phases having attractive electronic properties.