Jpn. J. Appl. Phys. 43 (2004) pp. 6371-6375  |Previous Article| |Next Article|  |Table of Contents|
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Formation of Aluminum Schottky Contact on Plasma-Treated Cadmium Telluride Surface

Hiroyuki Toyama, Atsushi Nishihira, Masaaki Yamazato, Akira Higa, Takehiro Maehama, Ryoichi Ohno1 and Minoru Toguchi

Faculty of Engineering, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan
1Acrorad Co., Ltd., 13-23 Suzaki, Gushikawa, Okinawa 904-2234, Japan

(Received March 20, 2004; accepted May 18, 2004; published September 9, 2004)

We have studied the effect of plasma treatment on the rectification property and performance of the CdTe radiation detector with the Al Schottky electrode. The Te-rich layer on the CdTe surface etched with Br-methanol caused the degradation of the rectification property of the Al/CdTe Schottky contact. To remove the Te-rich layer, plasma treatment was carried out. The plasma treatment did not roughen the CdTe surface, and it removed the Te-rich layer. In terms of current–voltage characteristics of the Al/CdTe Schottky contact, the leakage current of the samples with plasma treatment was lower than that of the samples without plasma treatment. Moreover, in terms of detector performance, the samples with plasma treatment showed a higher energy resolution than those without plasma treatment. We achieved a high energy resolution of 1.6 keV FWHM at 59.5 keV using the plasma-treated Al/CdTe/Pt detector, which is comparable to the value obtained using a conventional Schottky-type In/CdTe/Pt detector.

DOI: 10.1143/JJAP.43.6371
KEYWORDS:CdTe, plasma treatment, Al Schottky contact, stoichiometric surface, polarization

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