Vacuum 80 (2006) 908–913 Study of lithium behaviour in Si(Li) detectors A. Keffous a, , M. Siad b , A. Cheriet a , Y. Belkacem a , Y. Boukennous a , K. Bourenane a , A. Maallemi a , H. Menari a , W. Chergui a a Unite de Developpement de la Technologie du Silicium 02, Bd Frantz Fanon, B.P. 399 Alger-Gare, Algeria b Centre de Recherche Nucleaire d’Alger (CRNA), Algeria Received 15 June 2005; received in revised form 12 November 2005; accepted 12 December 2005 Abstract In this paper we describe the fabrication of a conventional lithium compensated silicon detector (Si(Li)) realized on Topsil silicon with bulk resistivity 0.9 to 3 kOcm, using the process of ion drift introduced by Pell. Preliminary results of electrical and nuclear characterization are shown. A leakage current value of 4 pA is obtained under reverse bias voltage of þ500 V, at pressure of 5:10 6 Torr and 113 K. An alpha test using triple source 241 Am, 239 Pu, 233 U was carried and a resolution on 241 Am peak around 42 keV was obtained with this type of detector. The fabricated detector present a good electrical and nuclear characteristics that can be used in X-ray spectrometry and widespread applications in research science, environment monitoring and natural radioactivity. The main contribution of this work is the demonstration of an easy-to-implement, low cost detector set that can be achieved with an inexpensive n þ p diode. r 2006 Elsevier Ltd. All rights reserved. Keywords: Lithium; Compensation; Solid-state detectors; Alpha spectrometry 0. Introduction The surface barrier detectors (SBD) have an insufficient of absorptivity over the useful zone (1 mm). This is why, with such detectors, one can undertake neither the study of the heavy particles of very high energies, nor those of the gamma radiations whose energy exceeds a few tens of keV. A different technique of manufacture makes it possible to produce semiconductor detectors whose useful zone can reach a depth of several mm. These are compensated detectors, the basic crystal being either silicon or germa- nium. The compensation of silicon by lithium helps creating important depleted zone giving intrinsic crystals [1–3]. Silicon lithium drifted detectors Si(Li) need to be cooled in almost liquid nitrogen temperatures for opera- tion. This characteristic renders such systems impractical for some applications in which there is not enough room to accommodate the bulky liquid nitrogen dewar. These types of detector have very low reverse current, smaller than 5 mA at room temperature, and very low output capacitance, which make them suitable to be used at room temperature. In recent years, the structures of silicon detector have been widely used in various research institutes. Nowadays the SBD structure is being thoroughly studied. Our scope of work is along this line. It consists of doping silicon with Lithium, thus obtaining after drift a very resistive substrate resulting in a large depleted zone due to the formation of Li þ 2B  complex. These silicon radiation detectors play an important role in industry, medicine and research due to their high-energy resolution, low leakage current, low applied voltage and high sensitivity. The study was carried out on p-type high purity silicon from TOPSIL (Denmark), 0.9 to 3kO cm resistivity and h111i oriented. 1. Experimental procedure 1.1. n þ p: Lithium junction The process achieved is classic and involves the following steps. The silicon wafers were cut using an ultrasonic machine with circular slices at different diameters from 8 to ARTICLE IN PRESS www.elsevier.com/locate/vacuum 0042-207X/$ - see front matter r 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.vacuum.2005.12.001 Corresponding author. Tel.: +213 21 43 44 44x263; fax: +213 21 43 35 11. E-mail address: keffousa@yahoo.fr (A. Keffous).