Dai Jin-Ji, Mai Thi Thu, Nallasani Umeshwar Reddy, Chang Shao-Chien, Hsiao Hsin-I, Wu Ssu-Kuan, Liu Cheng-Wei, Wen Hua-Chiang, Chou Wu-Ching, Wang Chieh-Piao, Hoang Luc Huy
Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
Technology Development Division, Episil-Precision Inc., Hsinchu 30010, Taiwan.
Materials (Basel). 2022 Mar 10;15(6):2058. doi: 10.3390/ma15062058.
The high electron mobility transistor (HEMT) structures on Si (111) substrates were fabricated with heavily Fe-doped GaN buffer layers by metalorganic chemical vapor deposition (MOCVD). The heavy Fe concentrations employed for the purpose of highly insulating buffer resulted in Fe segregation and 3D island growth, which played the role of a nano-mask. The in situ reflectance measurements revealed a transition from 2D to 3D growth mode during the growth of a heavily Fe-doped GaN:Fe layer. The 3D growth mode of Fe nano-mask can effectively annihilate edge-type threading dislocations and improve transfer properties in the channel layer, and consequently decrease the vertical leakage current by one order of magnitude for the applied voltage of 1000 V. Moreover, the employment of GaN:C film on GaN:Fe buffer can further reduce the buffer leakage-current and effectively suppress Fe diffusion.
通过金属有机化学气相沉积（MOCVD），在硅（111）衬底上制备了具有重掺杂铁的氮化镓缓冲层的高电子迁移率晶体管（HEMT）结构。为实现高绝缘缓冲层而采用的高铁浓度导致了铁的偏析和三维岛状生长，其起到了纳米掩膜的作用。原位反射率测量结果表明，在重掺杂铁的氮化镓：铁层生长过程中，生长模式从二维转变为三维。铁纳米掩膜的三维生长模式能够有效消除边缘型穿透位错，并改善沟道层中的传输特性，因此，对于1000V的施加电压，垂直漏电流降低了一个数量级。此外，在氮化镓：铁缓冲层上使用氮化镓：碳薄膜可以进一步降低缓冲层漏电流，并有效抑制铁的扩散。
