Jpn. J. Appl. Phys. 44 (2005) pp. 6742-6746  |Previous Article| |Next Article|  |Table of Contents|
|Full Text PDF (286K)| |Buy This Article|

Effect of He Plasma Treatment on the Rectification Properties of Al/CdTe Schottky Contacts

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

(Received December 16, 2004; revised May 10, 2005; accepted June 2, 2005; published September 8, 2005)

We investigated the effect of He plasma treatment on the surface composition of CdTe and the electrical properties of Al/CdTe Schottky contacts. The composition of the initial CdTe surface is Te-rich due to Br-methanol etching. When Al Schottky contacts are formed on the CdTe surfaces with the Te-rich layer, the barrier height is low and the rectification property is not good. In this paper, we propose the He plasma treatment method to remove the Te-rich layer. From X-ray photoelectron spectroscopy measurement, it was found that the plasma treatment can remove the Te-rich layer. The rectification property of the Al Schottky contacts on the plasma-treated surfaces is improved, and their barrier heights are estimated to be about 0.65 eV. In γ-ray spectrometry, a high-energy resolution of 1.6 keV full width at half maximum at 59.5 keV was obtained from the plasma-treated Al/CdTe/Pt detector. The results indicate that the plasma treatment of CdTe surfaces significantly improves the energy resolution of Schottky-type Al/CdTe/Pt radiation detectors.

URL: http://jjap.jsap.jp/link?JJAP/44/6742/
DOI: 10.1143/JJAP.44.6742

References | Citing Articles (10)

1. C. Scheiber and G. C. Giakos: Nucl. Instrum. Methods Phys. Res., Sect. A 458 (2001) 12.
2. K. Spartiotis, J. Havulinna, A. Leppänen, T. Pantsar, K. Puhakka, J. Pyyhtiä and T. Schulmam: Nucl. Instrum. Methods Phys. Res., Sect. A 527 (2004) 478.
3. T. Takahashi, K. Hirose, C. Matsumoto, K. Takizawa, R. Ohno, T. Ozaki and K. Mori: Proc. SPIE 3446 (1998) 29[AIP Scitation].
4. C. Matsumoto, T. Takahashi, K. Takizawa, R. Ohno, T. Ozaki and K. Mori: IEEE Trans. Nucl. Sci. 45 (1998) 428.
5. T. Takahashi, T. Mitami, Y. Kobayashi, M. Kouda, G. Sato, S. Watanabe, K. Nakazawa, Y. Okada, M. Funaki, R. Ohno and K. Mori: IEEE Trans. Nucl. Sci. 49 (2002) 1297.
6. T. Ozaki, Y. Iwase, H. Takamura and M. Ohmori: Nucl. Instrum. Methods Phys. Res., Sect. A 380 (1996) 141.
7. Z. Sobiesierski, I. M. Dharmadasa and R. H. Williams: Appl. Phys. Lett. 53 (1988) 2623[AIP Scitation].
8. I. M. Dharmadasa, J. M. Thornton and R. H. Williams: Appl. Phys. Lett. 54 (1989) 137[AIP Scitation].
9. R. L. Van Meirhaeghe, R. van de Walle, W. H. Laflère and F. Cardon: J. Appl. Phys. 70 (1991) 2200[AIP Scitation].
10. I. M. Dharmadasa: Prog. Cryst. Growth Charact. 36 (1998) 249.
11. H. Toyama, A. Nishihira, M. Yamazato, A. Higa, T. Maehama, R. Ohno and M. Toguchi: Jpn. J. Appl. Phys. 43 (2004) 6371[JSAP].
12. M. Funaki, T. Ozaki, K. Satoh and R. Ohno: Nucl. Instrum. Methods Phys. Res., Sect. A 436 (1999) 120.
13. D. W. Niles, X. Li, P. Sheldon and H. Höchst: J. Appl. Phys. 77 (1995) 4489[AIP Scitation].
14. M. A. Naby: Renewable Energy 6 (1995) 567.
15. T. L. Chu, S. S. Chu and S. T. Ang: J. Appl. Phys. 58 (1985) 4296[AIP Scitation].
16. J. G. Werthen, J.-P. Haring, A. L. Fahrenbruch and R. H. Bube: J. Appl. Phys. 54 (1983) 5982[AIP Scitation].
17. M. Niraula, A. Nakamura, T. Aoki, Y. Tomita and Y. Hatanaka: Nucl. Instrum. Methods Phys. Res., Sect. A 491 (2002) 168.