Study On Semi-consolidated Grinding And Chemical Mechanical Polishing Technology Of Easily Cleavable Gallium Oxide Crystals

Single crystal gallium oxide（β-Ga₂O₃）,as a typical representative of third-generation semiconductor materials,has good stability,an ultra-wide optical band gap of about 4.9e V（253nm）and excellent physical and chemical properties such as high transmittance in the ultraviolet-visible-near-infrared（UV-NIR）region,and has broad application prospects in high-power devices and ultraviolet photodetectors.However,due to its special hard and brittle properties,it is difficult to effectively improve the surface quality by traditional ultra-precision processing methods.Therefore,to explore the new ultra-precision processing method applicable toβ-Ga₂O₃ and to study the ultra-precision processing process ofβ-Ga₂O₃ has become an urgent problem to be solved.This paper takes the（100）and（010）crystal surfaces ofβ-Ga₂O₃ as the research object,and provides reference and guidance for the subsequent ultra-precision processing ofβ-Ga₂O₃ and even similar semiconductor materials through frictional wear,semi-solidified abrasive grinding,sub-surface damage detection and prediction,chemical mechanical polishing and other tests.The main research content of this paper is as follows:（1）Through friction and wear tests,the friction and wear properties of single crystal gallium oxide（100）crystal planes and（010）crystal planes were studied.The friction coefficient and wear rate of the two crystal planes of single crystal gallium oxide were analyzed under different p H environments,and their wear mechanisms were further explored,laying the foundation for subsequent gallium oxide crystal polishing work.（2）Through semi-consolidated abrasive grinding experiments,the influence of semi-consolidated abrasive grinding process parameters on the machining performance of semi-consolidated abrasive grinding pads is analyzed.Through orthogonal experiments,the grinding process parameters of single crystal gallium oxide semi-consolidated abrasive were optimized.The optimized material removal rates（MRR）of（100）crystal plane and（010）crystal plane were 3.786nm/min and 4.012nm/min,respectively;The surface roughness Ra of the（100）and（010）crystal planes are 26nm and 13nm,respectively,effectively suppressing the cleavage phenomenon of gallium oxide and significantly improving surface quality and processing efficiency.（3）By conducting subsurface damage detection and prediction experiments,the variation of subsurface damage depth during single crystal gallium oxide semi-consolidated abrasive grinding with grinding process parameters was studied.Based on the theory of indentation fracture mechanics,a prediction model for the depth of subsurface damage was established.The effectiveness of the prediction model was verified by the test results,and the accurate detection of subsurface damage was achieved.（4）Through chemical mechanical polishing experiments,a green and environmentally friendly chemical mechanical polishing solution suitable for single crystal gallium oxide was prepared.Through this,chemical mechanical polishing experiments were conducted on single crystal gallium oxide wafers to explore the influence of polishing process parameters on the polishing effect of single crystal gallium oxide.Further optimization of the chemical mechanical polishing process parameters for single crystal gallium oxide was carried out through orthogonal experiments.The optimized material removal rates（MRR）for（100）and（010）crystal planes were134.87nm/h and 139.19nm/h,respectively;The surface roughness Ra of the（100）crystal surface and the（010）crystal surface are 0.414nm and 0.356nm,respectively,which can achieve sub nanometer level polished surfaces.