Ion-Beam-Induced Damaging and Dynamic Annealing Processes in Silicon
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ION-BEAM-INDUCED DAMAGING AND DYNAMIC ANNEALING PROCESSES IN SILICON K.T. SHORT*, D.J. CHIVERS*t, R.G. ELLIMAN*F, J. LIU**, A.P. POGANY* H. WAGENFELD*, AND J.S. WILLIAMS* *Microelectronics Technology Centre, RMIT Melbourne 3000 Australia tPresent address: AERE Harwell, England; Joint appointment with CSIRO Division of Chemical Physics, Clayton 3168 Australia; ** Chinese Academy of Sciences, Beijing, China.
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ABSTRACT We have employed high resolution ion channeling and TEM methods to investigate the damage production and dynamic annealing processes which take place in (100) silicon bombarded at elevated temperatures. Two important observations have arisen from our results i) We have observed an amorphisation process for Sb-implanted silicon at 250 0 C which is more akin to amorphisation processes in metals, whereby the impurity (Sb) appears to influence the stability of amorphous zones associated with individual ion tracks. ii) We have demonstrated that previously amorphised layers in silicon can be recrystallised through a solid phase epitaxial process by subsequent bombardment with He+, Ar+ and Sb+ ions at 0 substrate temperatures of 300-400 C, which are significantly below normal thermal regrowth temperatures of >500 0 C.
INTRODUCTION At room temperature and below, it is well known that the implantation of heavy ions into silicon generates stable displacement damage and leads to amorphisation [1]. For elevated temperature implants there is a clear competition between damage production and dynamic annealing during ion bombardment. The amount and nature of the residual damage following elevated temperature implantation is particularly sensitive to several implantation parameters including ion species, dose, dose rate [2], substrate orientation[3] and implantation temperature[4,5]. If the implantation temperature is sufficient0 ly high (e.g.>300 C for Sb implantation) amorphous layers do not form and the residual damage consists of crystalline defect clusters and loops[3]. Furthermore, it has been recently demonstrated that it is possible to recrystallise previously amorphised silicon by ion bombardment of Ne+[61 and As+ [71 ions at temperatures of 300-4000 C which are significantly below the normal thermal recrystallisation temperatures of >500°C[8]. In this paper we report on two aspects of damage production and dynamic annealing processes in (100) silicon during elevated temperature ion bombardment. Firstly, amorphisation processes are examined for Sb implanted silicon and an intriguing dose dependence of damage production is observed 0 at 250 C. Secondly, we have observed epitaxial recrystallisation of previously amorphised silicon layers under He+, Ar+ and Sb+ bombardment at substrate 0 temperatures between 3000 and 400 C. EXPERIMENTAL We have previously carried out Sb implantation into (100) silicon at implantation temperatures between I2N2 and 450 0 C. The temperature,substrate orientation and dose dependencies of the implantation-induced damage were studied by ion channeling and TEM and the results have b
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