The Effect of Heavy Fe-Doping on 3D Growth Mode and Fe Diffusion in GaN for High Power HEMT Application |
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| Authors: | Jin-Ji Dai Thi Thu Mai Umeshwar Reddy Nallasani Shao-Chien Chang Hsin-I Hsiao Ssu-Kuan Wu Cheng-Wei Liu Hua-Chiang Wen Wu-Ching Chou Chieh-Piao Wang Luc Huy Hoang |
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| Affiliation: | 1.Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan; (J.-J.D.); (T.T.M.); (U.R.N.); (S.-C.C.); (H.-I.H.); (S.-K.W.); (C.-W.L.); (H.-C.W.);2.Technology Development Division, Episil-Precision Inc., Hsinchu 30010, Taiwan;3.Faculty of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi 10000, Vietnam |
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| Abstract: | ![]()
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. |
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| Keywords: | GaN power HEMT MOCVD Fe doping nano-mask 3D growth diffusion |
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