(山東大學(xué) 晶體材料國(guó)家重點(diǎn)實(shí)驗(yàn)室， 濟(jì)南 250100)
摘 要: 采用高純Si粉和C粉在適宜的溫度和壓力下合成了多晶SiC粉末， 在此基礎(chǔ)上采用升華法在低壓高溫下條件下生長(zhǎng)了大直徑6H-SiC單晶， 并根據(jù)熱力學(xué)理論分析了SiC的分解。 結(jié)果表明，在2300℃ 附近的生長(zhǎng)溫度下， Si， Si2C， SiC2是Si-C熱力學(xué)平衡下的主要物種，其平衡分壓比同組分的SiC物種高出3個(gè)量級(jí)， 因而是升華過(guò)程中的主要物種，其質(zhì)量傳輸過(guò)程直接決定SiC的生長(zhǎng)。另外， 采用光學(xué)顯微鏡觀察SiC單晶中的生長(zhǎng)缺陷，分析了缺陷成因， 提出了碳的包裹體是微管缺陷的重要來(lái)源， 而調(diào)制摻氮可以抑制部分微管在［0001］方向上的延伸， 并在此分析基礎(chǔ)上調(diào)整生長(zhǎng)參數(shù)， 生長(zhǎng)出了高質(zhì)量的6H-SiC單晶。
關(guān)鍵字: 升華法； SiC； 微管
HAN Rong-jiang, DONG Jie,JIANG Shou-zhen,
XU Xian-gang, WANG Ji-yang, JIANG Min-hua
（State Key Laboratory of Crystal Material , Shandong University, Jinan 250100, China）
Abstract:SiC powder was synthesized by using Si and C powder at favorable temperature and pressure. Then silicon carbide crystal was grown by the sublimation method under a low pressure and high temperature region. The decomposition reaction of SiC was simulated according to the thermodynamic theory. The result shows that the dominating species under thermodynamic equilibrium are Si,SiC2 and Si2C at about 2300℃. The equilibrium partial pressures of these three species are three magnitude degrees higher than those of the other species. Therefore, they are the main species during the sublimation process, and their mass flow determines the growth process. Furthermore, crystal defects were observed by optical microscopy. Carbon inclusions are the important origin of micropipes. It was found that the propagation of micropipes along the growth direction could be interrupted by modulation nitrogen doping. 6H-SiC of good quality is obtained after optimizing growth parameters.
Key words: sublimation method； SiC； micropipe
