MOVPE of AlN-free hexagonal GaN/cubic SiC/Si heterostructures for vertical devices

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• 作者：Jun Komiyama ; Yoshihisa Abe ; Shunichi Suzuki ; Hideo Nakanishi ; Akinori Koukitu
• 关键词：A1. Crystal structure ; A3. Metalorganic vapor phase epitaxy ; B1. Nitrides
• 刊名：Journal of Crystal Growth
• 出版年：2009
• 出版时间：1 May 2009
• 年：2009
• 卷：311
• 期：10
• 页码：2840-2843
• 全文大小：267 K

文摘

The heterostructures of GaN/SiC/Si were prepared without using AlN or AlGaN buffer layers (AlN buffers) in the metalorganic vapor phase epitaxy of GaN on SiC. GaN (0 0 0 1) with specular surface was obtained. The AlN buffers are usually used in the conventional growth of GaN on SiC due to the poor nucleation of GaN on SiC. Instead, the nucleation of GaN was controlled by varying the partial pressure of H₂ in the carrier gas, the mixture of H₂ and N₂, during the low-temperature (600 °C) growth of GaN (LT-GaN). After the LT-GaN, the high-temperature (1000 °C) growth of GaN was performed using pure H₂ as the carrier gas. The epitaxial film of cubic SiC (1 1 1) on a Si (1 1 1) substrate was used as the SiC template. Increasing the partial pressure of H₂ in the carrier gas decreased the coverage of SiC surface by LT-GaN. It is suggested that the hydrogen atoms adsorbed on the surface of SiC is preventing the nucleation of GaN.