Solid-Phase-Epitaxial Growth of Ion Implanted Silicon Using CW Laser and Electron Beam Annealing
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SOLID-PHASE-EPITAXIAL GROWTH OF ION IMPLANTED SILICON USING CWLASER AND ELECTRON BEAM ANNEALING* J. NARAYAN,
0. W. HOLLAND
Solid State Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830 and G. L. OLSON Hughes Research Laboratories, 3011 Malibu Canyon Road, Malibu, CA
90265
ABSTRACT The nature of residual damage in As+, Sb+, and In+ implanted silicon after CWlaser and e- beam annealing has been studied using plan-view and cross-section electron microscopy. Lattice location of implanted atoms and their concentrations were determined by Rutherford backscattering and channeling techniques. Maximum substitutional concentrations achieved by furnace annealing in a temperature range of 500-600 0 C have been previously reported [1] and greatly exceeded the retrograde solubility limits for all dopants studied. Higher temperatures and SPE growth rates characteristic of electron or cw laser annealing did not lead to greater incorporation of dopant within the lattice and often resulted in dopant precipitation. Dopant segregation at the surface was sometimes observed at higher temperatures. INTRODUCTION Ion implantation damage in silicon caused by moderate fluences of heavy ions generally consists of an amorphous layer followed by a band of dislocation loops. These loops below the amorphous layer are primarily created by ion range straggling. The number density of loops decreases with increasing mass of the incident ions, and decreasing substrate temperature and dose of the implanted ions. These amorphous layers on semiconductor substrates can be recrystallized either by solid-phase-epitaxial (SPE) or by liquid-phase-epitaxial (LPE) growth [1,2]. The SPE growth can be achieved in a furnace by heating the whole wafer, or by using CWlaser and e- beams which provide spatial and temporal selectivity. A characteristic feature following SPE growth is the presence of a band of dislocation loops below the original amorphous layer. This band is essentially the same band of dislocations that is present after implantation although the loops may coarsen and the number density decrease depending upon the details of the thermal treatment. These loops can be completely removed under LPE growth conditions, if the melt-depth, for example, induced by pulsed laser irradiation penetrates the dislocation band [2]. In this investigation, we have studied the residual damage using cross-section and plan-view electron microscopy. Dynamics of the crystallizing interface was monitored by timeresolved reflectivity techniques [3]. The dopant concentrations as a function of depth were studied by backscattering and channeling techniques. *Research sponsored by the Division of Materials Sciences, U. S. Department of Energy under contract W-7405-eng-26 with Union Carbide Corporation. Mat. Res.
Soc.
Symp. Proc.
Vol.
13 (1983)
Published by Elsevier Science Publishing Co.,
Inc.
156
S/
Fig. 1. Weak-beam TEM micrograph showing residual damage in seni implanted (100 keV As+, 5. 0Qx10 cm- ) and CW laser (Ar+ ion) annealing (lOW) silicon,
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