| Summary: | 碩士 === 國立交通大學 === 電子物理系所 === 97 === In this work , the relation between the process of polish and the micro-roughness on the surface of GaN substrate was the purpose we studied. The major purpose of this study is to develop the process of fabricating the GaN substrate suitable for epitaxial purpose for industrial applications. After we fabricated free-standing GaN thick film using laser lift-off technique, we planarized GaN with mechanical polish. The polished surface produced a root-mean-square surface roughness of 2 nm and we got removal rate. We made use of the technology of the chemical mechanical polish, which taking the colloidal silica solution with Slurries of C6H8O7 and NaOCl(or KOH and NaOCl) as the polishing solution,and then summed up the optimum process condition by changing the process parameters. Finally, with fine chemical mechanical polish step, the RMS roughness less than 1nm, and roughness of 0.5 nm on a 3X3 um2 scan area. Therefore, we are more confident with the quality of free-standing GaN substrate which is verified by AFM、PL and XRD.
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