【作者】 赵浙；

【导师】 叶志镇；

【作者基本信息】 浙江大学 ， 材料物理与化学， 2004， 硕士

【摘要】 宽禁带半导体GaN是制造蓝光光电器件和大功率、高温器件的理想材料。由于Si衬底的诸多优点：低价、存在高质量大尺寸单晶、好的热导和电导以及容易被化学刻蚀去除，硅基GaN成为研究的热点。由于体单晶难以制备，生长高质量的薄膜单晶材料是研究开发GaN基器件的基本前提条件。与蓝宝石衬底相比，由于GaN在硅上难以浸润及GaN和Si之间大的热失配和晶格失配等特点，硅上生长单晶GaN的难度很大。到目前为止，制造出高质量的硅基GaN器件仍然是很有挑战性的工作。 本论文在系统总结了国内外GaN材料制备和器件应用的研究历史和现状的基础上，利用自行开发研制的MOCVD设备，对硅衬底上GaN的外延生长和p型掺杂进行了研究，取得了一些阶段性的成果。 主要工作如下： 1．使用自行开发的MOCVD系统，利用高温AIN缓冲层，在Si（111）衬底上成功生长出GaN单晶。测试显示晶体质量达到560arcsec，是文献报道过最好的结果之一。 2．采用Cp₂Mg做掺杂源，成功获得了硅基GaN的p型电导。Hall测试结果：载流子浓度达到7.84×10¹⁸cm^-3，迁移率为5.50cm²／V．s，显示了我们生长的硅基p-GaN具有良好的电学性能；HRXRD测试得到该材料半高宽达到560arcsec，说明了它具有很好的晶体质量。 3．研究了快速热退火（RTA）对p型GaN中位错的影响。我们发现RTA对GaN中螺型位错的影响很大，而刃型位错则在RTA下比较稳定。通过分析当前条件下位错的核心结构的形成能，就RTA处理对不同种类位错的影响做出了初步的解释。更多还原

【Abstract】 GaN is a promising material for blue opto-electronic devices and high-power, high-temperature devices. Due to the numerous advantages of Si substrate: low cost, large scale availability with high quality, good thermal and electrical conductivities, and possible removing by chemical etching, many groups are working to fabricate GaN-based devices on Si substrate. Up to date, it is still very hard to grow GaN bulk crystals, so the heteroepitaxial growth of high quality GaN thin films is the premise for the development of GaN-based devices. Compare to sapphire substrate, the poor nucleation and the difference in thermal and lattice coefficient between GaN and Si make it difficult to grow high quality GaN film on Si. It is still a challenge work to fabricate GaN-based devices on Si substrate.In this paper, a comprehensive review of the research history and current status of GaN material preparation and characterizations are discribed. On the basis of home-made MOCVD system, we carried out a detailed study of GaN epitaxy and p-type doping on silicon substrates is conducted and achieved some encouraging results.The main work are summerised as the following:1. Wurtzite single crystalline GaN on Si (111) substrates using high-temperature A1N as a buffer layer in a home-made MOCVD system is reported. HRXRD and SEM indicated a very good crystal quality, which was among the best results ever reported.2. P-type conductivity was succesesfuly achieved using Cp2Mg as precursor via MOCVD system. The carrier concentration and mobility of p-type GaN were 7.84 l0-8 cm-3 and 5.50cm2/V.s respectively, characterized by van der Pauw Hall measurement. HRXRD showed very good crystal quality.3. The relationship between rapid thermal annealing(RTA) and the dislocations in p-doped GaN via MOCVD was studied. The core structure models of dislocations were used to interpret the relations we have found.更多还原