高光效LED氮化镓衬底的无损伤机械-化学交互材料微观去除机制研究

高发光效率氮化镓(GaN)基LED对GaN同质衬底的化学机械抛光(CMP)质量提出了严苛要求。由于缺乏对GaN材料机械-化学交互微观去除机制的科学认识，目前GaN衬底的CMP加工存在材料去除率低、全局平坦化缺陷控制难等问题。为此，本项目拟从微观磨损角度，借助原子力显微镜等手段，独立研究单个磨粒在抛光液环境中对GaN材料的无损伤机械-化学交互微观去除机制。在探明机械作用、化学作用及机械-化学交互作用下的材料微观去除规律的基础之上，结合微区化学成分和晶格分析，深入研究去除过程中机械作用和化学作用的交互关系、交互作用下晶格损伤产生与消除的动态平衡机制，进而探讨无损伤的机械-化学交互材料微观去除机理。最后通过优化提出无损伤、高速率的材料微观去除条件，进行CMP实验验证。预期成果可丰富纳米摩擦学和超精密加工的基础理论，为高光效GaN基LED应用中GaN同质衬底的高质量、高效率CMP加工提供理论指导。

High-luminaire-efficiency GaN-based LED has put forward a high request for the chemical mechanical polishing (CMP) quality of GaN homogeneous substrate. Due to the lack of the scientific understanding on the material microscopic removal mechanism of GaN under mechano-chemical interaction, the material removal rate is low and defect-control in global planarization is hard during CMP process of GaN. To solve this problem, we will study the mechanism of nondestructive microscopic material removal of GaN by single abrasive particle in the polishing fluid environment with atomic force microscopy and other equipment from microwear view. Firstly, material microscopic removal rules under mechanical interaction, chemical etching and mechano-chemical interaction will be investigated respectively. Then, combined with the analysis of chemical composition and lattice feature on material removal area, mechano-chemical interaction relationship, the dynamic balance mechanism of lattice damage generation and eliminatition under mechano-chemical interaction will be further studied. The nondestructive microscopic material removal mechanism of GaN via mechano-chemical interaction will be discussed. Finally, we will propose the nondestructive and high rate removing condition through optimization, and then carry out the experimental verification on CMP device. The expected results would not only enrich the basic theory on nanotribology and ultraprecision machining, but also help to provide theoretical guidance for high quality and high efficiency CMP fabrication on GaN homogeneous substrate for GaN-based LED.