Study on Lapping Mechanism of Different Crystal Planes of Indium Phosphide: Molecular Dynamics Simulation and Experimental Verification

XN Wen and JY Deng and ZL Bai and JC Geng and H Wei and HB Liu and F Qiu and F Hui, LANGMUIR, 41, 23850-23866 (2025).

DOI: 10.1021/acs.langmuir.5c03109

The unknown mechanism of lapping damage on different InP crystal surfaces constrains the device performance optimization. This study establishes a molecular dynamics (MD) model for nanoscale lapping of InP (100)/(110)/(111) surfaces using the Vashishta potential, combined with gradient lapping experiments (1 mu m rough, 500 nm fine, 100 nm ultrafine diamond grits), to systematically reveal differences in material removal mechanisms and surface quality. The results show that the MD simulation agrees well with the experiments. The simulation predicts that the (100) crystal face has the highest material removal due to continuous chip formation, and the experiment confirms that it has the highest material removal rate (181.27 mu m/h). In terms of surface quality, the simulation showed that the (100) crystalline face had the best atomic plastic flow; the (110) crystalline face needed to accumulate a critical amount of chips to activate plastic flow, and the (111) crystalline face had the worst plasticity. Morphological inspection shows that the lowest roughness (Sa = 2.126 nm) is obtained for the (100) crystalline surface, but deep scratches lead to large error fluctuations; the (110) and (111) crystalline surfaces show surface chipping due to abrasive grain sizes close to the critical value for brittle-plastic transition. It is demonstrated that the grain surface orientation dominates the material removal mechanism by regulating the activation of the slip system and dislocation evolution, which provides a theoretical basis for the selective processing of InP wafers and the optimization of device performance.

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