Abstract

The B3-GaN thin film was investigated by performing large-scale molecular dynamics (MD) simulation of nanoindentation. Its plastic behavior and the corresponding mechanism were studied. Based on the analysis on indentation curve, dislocation density, and orientation dependence, it was found that the indentation depths of inceptive plasticity on (001), (110), and (111) planes were consistent with the Schmid law. The microstructure evolutions during the nanoindentation under different conditions were focused, and two formation mechanisms of prismatic loop were proposed. The “lasso”-like mechanism was similar to that in the previous research, where a shear loop can translate into a prismatic loop by cross-slip; and the extended “lasso”-like mechanism was not found to be reported. Our simulation showed that the two screw components of a shear loop will glide on another loop until they encounter each other and eventually produce a prismatic dislocation loop.

Highlights

  • Group-III metal nitrides are a kind of interstitial compounds, which have caused extensive concern in the past decade

  • With the advance of preparation technology, the B3-gallium nitride (GaN) can be fabricated with the modified surface-activated-bonding (SAB) method at room temperature [6]

  • To confirm the reliability of this potential for B3-GaN, the basic parameters, such as bulk modulus, lattice constant, cohesive energy, and elastic constants, are calculated with molecular dynamics (MD) simulation and compared to those obtained by experiments or density functional theory (DFT)

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Summary

Introduction

Group-III metal nitrides are a kind of interstitial compounds, which have caused extensive concern in the past decade. Gallium nitride (GaN) is a wide-band gap semiconductor and is supposed to be one of the most popular candidates because of its dystectic point, high frequency, and high-power [2]. With the advance of preparation technology, the B3-GaN can be fabricated with the modified surface-activated-bonding (SAB) method at room temperature [6] When this promising semiconductor material is in service, it may be subjected to pressure, inducing micro-structural deformation. The research on the structural deformation in GaN films is not enough, for the B3 structure Their mechanical properties need to be further investigated. An innovative stress-driven nonlocal integral elasticity model was proposed for the size-dependent analysis, which can avoid the difficulties of the classical strain-driven nonlocal law [10] These methods cannot solve some issues, such as how a prismatic loop forms and propagates.

Selection of Potentials
Structure Identification
Deformational Behavior of GaN under Indentation
NR mi vim vin

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