氮化物宽禁带半导体的MOCVD大失配异质外延

Large Lattice-Mismatched Heteroepitaxial Growth of Nitride Wide Bandgap Semiconductors by MOCVD

以氮化镓(GaN)、AlN(氮化铝)为代表的Ⅲ族氮化物宽禁带半导体是研制短波长光电子器件和高频、高功率电子器件的核心材料体系。由于缺少高质量、低成本的同质GaN和AlN衬底,氮化物半导体主要通过异质外延,特别是大失配异质外延来制备。由此导致的高缺陷密度、残余应力成为当前深紫外发光器件、功率电子器件等氮化物半导体器件发展的主要瓶颈,严重影响了材料和器件性能的提升。本文简要介绍了氮化物半导体金属有机化学气相沉积(MOCVD)大失配异质外延的发展历史,重点介绍了北京大学在蓝宝石衬底上AlN、高Al组分AlGaN的MOCVD外延生长和p型掺杂、Si衬底上GaN薄膜及其异质结构的外延生长和缺陷控制等方面的主要研究进展。最后对Ⅲ族氮化物宽禁带半导体MOCVD大失配异质外延的未来发展做了简要展望。

Ⅲ-nitride wide bandgap semiconductors,such as gallium nitride(GaN)and aluminum nitride(AlN),are the key materials for the development of short-wavelength optoelectronic devices,as well as high-frequency and high-power electronic devices.Due to the lack of high-quality and low-cost homogeneous GaN and AlN substrates,nitride semiconductors are mainly realized by means of heteroepitaxy,especially the large lattice-mismatched heteroepitaxy,resulting in high defect density and huge residual stress in the epilayers,which have become the key bottlenecks in the development of deep ultraviolet light emitting devices and power electronic devices,and other nitride semiconductor ones.In this paper,the research history of the large lattice-mismatched heteroepitaxy of nitride semiconductors by means of metal organic chemical vapor deposition(MOCVD)is first briefly introduced.Then,the research progress on the MOCVD epitaxial growth and p-type doping of AlN and high Al composition AlGaN on sapphire substrate,as well as the MOCVD epitaxial growth and defect control of GaN and its heterostructures on Si substrate in Peking University are demenstrated.Finally,the current challenges and developing trends on the large lattice-mismatched heteroepitaxy forⅢ-nitride wide bandgap semiconductors are reviewed and expected.