Formation of the intermediate semiconductor larger for the Ohmic contact to silicon carbide using Germanium implantation
Guo Hui(郭辉)a)†, Wang Yue-Hu(王悦湖)a), Zhang Yu-Ming(张玉明)a), Qiao Da-Yong(乔大勇)b), and Zhang Yi-Men(张义门)a)
a Microelectronics School, Xidian University, Xi'an 710071, China and Key Lab of Wide Band-Gap Semiconductor Materials and Devices, Xi'an 710071, China; b Micro and Nano Electromechanical Systems Laboratory, Northwestern Polytechnical University, Xi'an 710072, China
Abstract By formation of an intermediate semiconductor layer (ISL) with a narrow band gap at the metallic contact/SiC interface, this paper realises a new method to fabricate the low-resistance Ohmic contacts for SiC. An array of transfer length method (TLM) test patterns is formed on N-wells created by P+ ion implantation into Si-faced p-type 4H-SiC epilayer. The ISL of nickel-metal Ohmic contacts to n-type 4H-SiC could be formed by using Germanium ion implantation into SiC. The specific contact resistance $\rho_{\rm c}$ as low as 4.23× 10-5 $\Omega\cdot$cm2 is achieved after annealing in N2 at 800 °C for 3 min, which is much lower than that (>900 °C) in the typical SiC metallisation process. The sheet resistance Rsh of the implanted layers is 1.5 k$\Omega$/$\Box$. The technique for converting photoresist into nanocrystalline graphite is used to protect the SiC surface in the annealing after Ge+ ion implantations.
Received: 13 January 2009
Revised: 07 April 2009
Accepted manuscript online:
(Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization)
Fund: Project supported by the National
Natural Science Foundation of China (Grant No J54508250120) and
Xi'an Applied Materials Innovation
Fund (Grant No XA-AM-200704).
Cite this article:
Guo Hui(郭辉), Wang Yue-Hu(王悦湖), Zhang Yu-Ming(张玉明), Qiao Da-Yong(乔大勇), and Zhang Yi-Men(张义门) Formation of the intermediate semiconductor larger for the Ohmic contact to silicon carbide using Germanium implantation 2009 Chin. Phys. B 18 4470
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