Study On Simulation And Experimental Of Single Crystal GaN Nano-Cutting

As the third generation semiconductor material,single crystal gallium nitride has the characteristics of large band gap,high critical breakdown electric field,stable chemical properties,etc.compared with other semiconductor materials(single crystal silicon,single crystal germanium,gallium arsenide),Therefore,it is more widely used in important fields such as aerospace,cutting-edge technology and ultra-precision instrument manufacturing.At present,the research on single crystal gallium nitride mainly focuses on the preparation of materials,and there are few studies on its processing characteristics and microscopic deformation mechanism during ultra-precision processing,which seriously affects and restricts the improvement of its processing quality and the use of gallium nitride devices Further performance improvements.Therefore,this paper uses a combination of molecular dynamics simulation and experiment to study its nano-processing process.The specific research contents of this paper are as follows:1.The single crystal gallium nitride(100),(110),(111)crystal plane simulation model is established.Three processes are carried out through the process load-displacement curve,deformation area change,unloading elastic recovery,atomic deformation process and hardness value.A comparative analysis of the seed crystal planes shows that the(111)crystal plane has the lowest hardness value and is most susceptible to deformation under stress.It is preferred that it is a machined surface.The nano-indentation experiment of the single crystal gallium nitride(100)crystal plane was carried out.The atomic force microscope was used to observe the morphology of the processed surface.The load-displacement curve,hardness and elastic modulus curve and elastic deformation of the single crystal gallium nitride were analyzed.During the recovery process,the(100)crystal surface hardness value was 6.55GP,which was in agreement with the simulation results.2.Simulate the effects of cutting parameters(cutting speed,cutting thickness)and tool geometry(tool rake angle,tool geometry)on the cutting force,damage layer thickness,temperature and potential energy,and material deformation of the single-crystal GaN nanoprocess.The simulation shows that different cutting speeds and different cutting thicknesses have certain effects on its cutting processing,but from the perspective of cutting force,single-crystal GaN nano-cutting is more sensitive to the processing thickness.Simultaneously,the variable-depth cutting simulation was conducted to study its elastoplastic deformation process.The critical deformation load was 225nN and the critical deformation depth was 4.8nm.3.Carry out the nano-scoring experiment of the single crystal gallium nitride(100)crystal plane to study the brittle-plastic transformation mechanism of the variable load scratch process.It was observed that cracks appeared in the brittle removal process and were symmetrically distributed along the 45°.The critical loads of brittle-plastic transformation are 389mN and 1227mN,respectively.Finally,the effect of cutting parameters(cutting speed,cutting thickness)on the surface cutting mechanism of single crystal gallium nitride material was studied.The cutting force and friction coefficient analysis showed that the cutting thickness had a greater effect on the single crystal gallium nitride nanoscratch process.The accuracy of the simulation is verified.