Nucleation & Growth of Octahedral Oxide Particles in Silicon: Oxygen Ion Implantation
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NUCLEATION & GROWTH OF OCTAHEDRAL OXIDE PARTICLES IN SILICON: OXYGEN ION IMPLANTATION R.W. CARPENTER*, G. VANDERSCHAEVE*+, C.J. VARKERA* AND S.R. WILSON** *Center for Solid State Science, Arizona State University, Tempe, AZ 85287. **Motorola Semiconductor Research and Development Laboratories, Phoenix, AZ 85008. +Permanent Address: Laboratory for Structure & Properties of the Solid State, Universite des Sciences et Techniques de Lille, Villeneuve d'Ascq 59655, France. ABSTRACT Czochralski silicon was implanted wi9 oxygen at 3 0.4 and 3.5MeV to obtain concentrations near 10 oxygen/cm in the implanted region. Following implantation the wafers were aged at about 10000C for 7 hours, and the resulting precipitates were examined y HRJM. A high density of octahedral SiO precipitates (-10 /cm-) was the dominant morphology. Platf type precipitates and dislocations were also present at lower density. The data indicate octahedra grow from the plates. INTRODUCTION The most common oxide precipitate morphological forms observed in thermally aged CZ-Si are (100) plates, octahedra bounded by (111) planes, and precipitate-dislocation complexes (1). Our present interest is the relationship between the plate and octahedral morphologies. Octahedra have been considered to be the equilibrium morphology for high temperature (-1200 0 C) thermal aging, but have also been observed in CZ-Si of relatively high carbon content after single step 0 750 C or two step low/high aging at -800/1050 0 C (2,4). This paper reports high resolution electron microscopy observations of oxide precipitate morphology in CZ-Si implanted with oxygen ions, and then post-implantation annealed in nearly the same temperature range (900 to 10500C). Implantation doses were chosen to produce oxygen concentrations at the projected range., Rp, at least an order of magnitude higher than the solubility limit at the Si melting point, to minimize the effect of carbon on the resulting morphology, and to provide a strong driving force for the precipitation reaction, to ensure a high nucleation rate near Rp. EXPERIMENTAL METHOD Single crystal p-type wafers of 0.020 inch thickness with (100> surface normal were sliced from a CZ ingot and polished for implantation. Oxygen and carbon concentrations, meIgured by stangrd 3FTIR methods, were ýp t~e ranges 0.97x10 to 1.87x10 cm and 3.40 to 15.3xl0- cm , respectively. Oxygen was implanted
at 0.4
and 3.5MeV at
doses up
to
Mat. Res. Soc. Symp. Proc. Vol. 59. &1986 Materials Research Society
Downloaded from https://www.cambridge.org/core. Access paid by the UCSB Libraries, on 21 Jul 2018 at 08:53:11, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/PROC-59-309
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16 -2 ixl0 cm -. Rp at these two incident energies are about 1 and 4 microns, respectively. Calculated peak oxygen concentrations at Rp are given in Table I. TABLE I Maximum oxygen concentrations at Rp, Energy,
MeV
0.4 0.4
3.5 3.5
Rp,
1m
0.9 0.9
3.9
3.9
Oxygen at.cm-3 20
3x10 9x10 1 9 6x0 19
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