【摘要】 本文研究了SOI衬底上采用MOCVD方法生长GaN材料的应力释放机制。采用SIMOX工艺制备的具有薄膜顶层硅的SOI材料作为外延生长的衬底材料,采用MOSS在位检测系统以及拉曼测试作为GaN内部应力的表征手段。结果表明,SOI材料对硅基GaN异质外延中的晶格失配应力和热应力的释放都有显著作用。薄膜SOI材料通过顶层硅与外延层的界面滑移,将一部分晶格失配应力通过界面的滑移释放,并且通过柔性薄膜顶层硅自身的应力吸收作用,将一部分热失配应力转移到衬底,从而有效地降低了GaN外延层的张应力。更多还原

【Abstract】 The stress reduction in GaN epilayer deposited on SOI substrates by metal-organic chemical vapor deposition(MOCVD) was studied.The SOI wafers fabricated by separation by implanted oxygen(SIMOX) technology with thin top silicon layer were used as the substrate.The in-situ multiple beam optical stress sensor(MOSS) system and Raman spectra were used to characterize the stress in GaN epilayer.The results show that the SOI substrate can obvious reduce the lattice mismatch and thermal expansion coefficient mismatch stress in GaN epilayer on silicon.The thin film SOI substrates can partially relax the lattice mismatch stress by the floating in the epilayer and top silicon interface,and the thermal expansion coefficient mismatch stress can partially transfer to the SOI substrate by the compliant thin top silicon layer absorbing the tensile stress.So the SOI substrates are helpful for the stress reduction in the GaN epilayer.更多还原