Molecular dynamics simulation of AFM tip-based hot scratching of nanocrystalline GaAs

Pengfei Fan, Saurav Goel, Xichun Luo, Yongda Yan, Yanquan Geng, Yang He, Yuzhang Wang

Research output: Contribution to journalArticlepeer-review

Abstract

GaAs is a hard, brittle material and its cutting at room-temperature is rather difficult, so the work explored whether hot conditions improve its cutting performance or not. Atomic force microscope (AFM) tip-based hot machining of the (0 1 0) oriented single crystal GaAs was simulated using molecular dynamics (MD). Three representative temperatures 600 K, 900 K and 1200 K (below the melting temperature of ~1511 K) were used to cut GaAs to benchmark against the cutting performance at 300 K using indicators such as the cutting forces, kinetic coefficient of friction, cutting temperature, shear plane angle, sub-surface damage depth, shear strain in the cutting zone, and stress on the diamond tip. Hotter conditions resulted in the reduction of cutting forces by 25% however, the kinetic coefficient of friction went up by about 8%. While material removal rate was found to increase with the increase of the substrate temperature, it was accompanied by an increase of the sub-surface damage in the substrate. Simulations at 300 K showed four major types of dislocations with Burgers vector 1/2<110>, 1/6<112>, <0-11> and 1/2<1-12> underneath the cutting zone and these were found to cause ductile response in zinc-blende GaAs. Lastly, a phenomenon of chip densification was found to occur during hot cutting which referred to the fact that the amorphous cutting chips obtained from cutting at low temperature will have lower density than the chips obtained from cutting at higher temperatures.
Original languageEnglish
JournalMaterials Science in Semiconductor Processing
Publication statusAccepted/In press - 20 Mar 2021

Keywords

  • AFM tip-based hot machining
  • molecular dynamic (MD) simulation
  • single crystal gallium arsenide
  • dislocation nucleation

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