Study of lithium behaviour in Si(Li) detectors

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 , 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 , at pressure of and 113 K. An alpha test using triple source ²⁴¹Am, ²³⁹Pu, ²³³U was carried and a resolution on ²⁴¹Am 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⁺p diode.     

Lithium diffusion profile onto highly resistive p-type silicon

In this work, the effect of temperature and time of diffusion on the lithium (Li) profile into p-type highly resistive silicon have been investigated. The high-purity Li metal (99.995%) was deposited onto p-type (1 1 1) silicon surface and thermally diffused into the bulk at a 2×10⁻⁶ Torr vacuum pressure. The four-probes technique was used to determine the diffusion profile of Li impurities into silicon. Scanning electron microscopy (SEM) was used to measure the diffused junction depth (X_j). The Li diffusion constant D_Li was then extracted using the measured surface concentration N_Li. Thus, the variation of D_Li as a function of diffusion temperature was determined. Simulated profiles was obtained by means PC1D calculate tool. A good agreement was found when the simulated and experimental results were compared with those of the literature values.