Characterization of Damage Induced by Cluster Ion Implantation
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Characterization of Damage Induced by Cluster Ion Implantation Takaaki Aoki1,2, Jiro Matsuo2 and Gikan Takaoka2 Osaka Science and Technology Center, Utsubo-honmachi, Nishi-ku, Osaka 550-0004, JAPAN 2 Ion Beam Engineering Experimental Laboratory, Kyoto University, Sakyo, Kyoto 606-8501, JAPAN 1
ABSTRACT Molecular dynamics simulations of boron monomer and small clusters (B4 and B10) impacting on Si(001) were performed in order to investigate the damage formation by monomer/cluster impact. These monomer and clusters show similar implant depth and efficiency, but different damage structures. At the impact of B monomer with 230eV of incident energy, some point-defects such as vacancy-interstitial pairs are mainly formed. On the other hand B10 produces several times larger number of vacancies and interstitials compared with B1, This damage structure is different from one by B1 implantation and due to high yield amorphization of implanted region. This characteristic damage formation process is expected to cause different annihilation process.
INTRODUCTION As the scale of LSI device decreases, the formation of ultra shallow p-type junction becomes more important. Cluster ion implantation using small boron cluster, decaborane (B10H14), has been introduced as a candidate for ultra shallow junction formation. Both experiments [1,2] and molecular dynamics (MD) simulations [3] of small B cluster and monomer implantation has been performed. When a B cluster, with the size below 10 and the energy of several hundreds eV per atom, impacts on Si substrate, the cluster breaks up in the substrate and each B atom penetrates into the substrate independently. Therefore, the depth profile of B atoms by cluster implantation was as same as those by B monomer ion with same energy per atom. Additionally, it is important to understand the damage formation process, because the annealing after ion implantation causes transient enhanced diffusion (TED) of dopant [4,5], which is one of the problems to fabricate high-quality shallow junction. It has been considered that, the TED has close relation to the structure of damage formed by ion implantation. As in previous work [6], when a B10H14 is implanted with 3keV, the TED is suppressed at 900°C of annealing temperature. On the other hand, the recent work about low-energy boron monomer implantation reported that the TED is also reduced by 500eV of B monomer implantation [7]. It is needed to discuss the similarity and difference between monomer and cluster implantation processes. In this paper, MD simulations of B1, B4 and B10 clusters impacting on Si(001) substrate are performed. The defects induced by ion impact are classified into vacancies and interstitials. The distribution and structures of these defects were examined. The difference of damage formation and annihilation mechanism between monomer and cluster impact will be discussed.
J4.5.1
SIMULATION MODEL In order to examine the damage formation process by small boron cluster impacts, the MD simulations of B1, B4 and B10 monomer/cluster imp
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