Investigation of cracking in monocrystalline silicon induced by high- temperature indentation

A simulation model of the indentation process via Berkovich indenter with cohesive interface elements and changeable temperature condition was developed. The indentation curves and imprints obtained by simulation were compared with experimental results. Compared with room temperature, the hardness of monocrystalline silicon decreases by 7.2 % at 400 °C, while it decreases dramatically by 64.3 % at 600 ℃. The initiation and expansion process of monocrystalline silicon cracks are investigated through the evolution of the scalar degradation parameter (SDEG). The original location of the half-penny crack changes from beneath the center of the imprint at room temperature to the edge region at 400 °C. The half-penny cracks were replaced by radial cracks at 500 ℃, and no crack formation occurs at 600 ℃. Stresses S11 and S22 were examined to investigate the evolution of surface and internal cracks in monocrystalline silicon. This analysis revealed the phenomenon of median crack closure under compressive stresses and a reduced cracking threshold under elevated temperatures.