TY - JOUR

T1 - Exploring the high-temperature deformation behavior of monocrystalline silicon – An advanced nanoindentation study

AU - Schaffar, Gerald

AU - Tscharnuter, Daniel

AU - Maier-Kiener, Verena

N1 - Publisher Copyright: © 2023 The Authors

PY - 2023/7/29

Y1 - 2023/7/29

N2 - Knowing the mechanical behavior of silicon at elevated temperatures is crucial for many high-temperature applications and processes. This work aims to expand the knowledge of these properties, especially on length scales relevant to miniaturized silicon structures. Therefore, nanoindentation experiments were performed on two differently doped (1 0 0) silicon wafers with varying oxygen content, from room temperature up to 950 °C. Residual impressions were microscopically characterized via confocal laser scanning microscopy. From this dataset covering an exceptionally large temperature range the elastic modulus and hardness as well as strain rate sensitivity, activation volume, and energy were evaluated. Generally, a change in deformation behavior can be identified between 300 °C and 400 °C. Above this transition temperature, the hardness drops exponentially. Also, the material becomes strain rate sensitive. These observations support the assumption that the deformation mechanism shifts from high-pressure phase transformation to dislocation-controlled plasticity with increasing temperature. Furthermore, a change in strain rate sensitivity, activation energy, and activation volume above 800 °C implies a further shift in the rate-controlling mechanism of dislocation motion. Lastly, the more strongly doped sample with the higher oxygen content showing higher mechanical strength is discussed regarding solid-solution strengthening and dislocation locking by oxygen atoms.

AB - Knowing the mechanical behavior of silicon at elevated temperatures is crucial for many high-temperature applications and processes. This work aims to expand the knowledge of these properties, especially on length scales relevant to miniaturized silicon structures. Therefore, nanoindentation experiments were performed on two differently doped (1 0 0) silicon wafers with varying oxygen content, from room temperature up to 950 °C. Residual impressions were microscopically characterized via confocal laser scanning microscopy. From this dataset covering an exceptionally large temperature range the elastic modulus and hardness as well as strain rate sensitivity, activation volume, and energy were evaluated. Generally, a change in deformation behavior can be identified between 300 °C and 400 °C. Above this transition temperature, the hardness drops exponentially. Also, the material becomes strain rate sensitive. These observations support the assumption that the deformation mechanism shifts from high-pressure phase transformation to dislocation-controlled plasticity with increasing temperature. Furthermore, a change in strain rate sensitivity, activation energy, and activation volume above 800 °C implies a further shift in the rate-controlling mechanism of dislocation motion. Lastly, the more strongly doped sample with the higher oxygen content showing higher mechanical strength is discussed regarding solid-solution strengthening and dislocation locking by oxygen atoms.

UR - http://www.scopus.com/inward/record.url?scp=85166740759&partnerID=8YFLogxK

U2 - 10.1016/j.matdes.2023.112198

DO - 10.1016/j.matdes.2023.112198

M3 - Article

VL - 2023

JO - Materials and Design

JF - Materials and Design

SN - 0264-1275

IS - 233

M1 - 112198

ER -