Mechanical-stressing measurements of formation energy of single Shockley stacking faults in 4H-SiC
Koji Maeda, Koichi Murata, Isaho Kamata, Hidekazu Tsuchida
Abstract
Abstract The formation energy <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi>γ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">ISSF</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">eq</mml:mi> <mml:mo>.</mml:mo> </mml:mrow> </mml:msubsup> </mml:math> of single Shockley stacking faults (1SSFs) in thermo-equilibrium is crucial for validating the anomalous expansion mechanism of 1SSF induced by forward current injection in 4H-SiC bipolar devices. As a function of variable mechanical stress externally applied to a plate sample of 4H-SiC, we systematically measured the ultraviolet intensity thresholds demarcating photo-induced expansion and contraction of 1SSFs. The experimental results on two types of 1SSF differing in the Schmid factor of mobile partial dislocations achieving 1SSF expansion/contraction showed a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi>γ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">ISSF</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">eq</mml:mi> <mml:mo>.</mml:mo> </mml:mrow> </mml:msubsup> </mml:math> value of 4.7 ± 1.6 mJ m −2 , significantly smaller than the reported value of 14 ± 2.5 mJ m −2 obtained by transmission electron microscopic measurements.