Abstract
This study uses the in-situ high-temperature nanoindentation coupled with electrical measurements to investigate the temperature dependence (25 to 200°C) of the phase transformation behavior of crystalline silicon (dc-Si) at the nanoscale. Along with in-situ indentation and electrical data, ex-situ characterizations such as Raman and cross-sectional transmission electron microscopy (XTEM) have been used to reveal the dominant mode of deformation under the indenter. In contrast to the previous studies, the dominant mode of deformation under the nanoindenter at elevated temperatures is not the dc-Si to metallic phase (β-Sn) transformation. Instead, XTEM images from ≥ 150°C indents reveal that the dominant mode of deformation is twinning along {111} planes. While the in-situ high-temperature electrical measurements show an increase in the current due to metallic phase formation up to 125°C, it is absent ≥ 150°C, revealing that the formation of the metallic phase is negligible in this regime. Thus, this work provides clear insight into the temperature dependent deformation mechanisms in dc-Si at the nanoscale.
