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SAMEER A.DATAR , H.E. GOVE, R.TENG AND J. P. LAVINE Nuclear Structure Research Laboratory, University of Rochester, Rochester, NY 14627 Microelectronics Technology Division, Eastman Kodak Company, Rochester, NY 14650-2008

ABSTRACT The diffusion of implanted chlorine in silicon wafers is studied with Depth neutron activation/accelerator mass spectroscopy (NA/AMS). profiles are obtained from as-implanted and annealed samples. While there is a marked difference between the annealed and as-implanted profiles for the lowest implant dose studied, 101 3/cm 2 , the chlorine from the higher dose implants is virtually immobile. The diffusion of implanted chlorine in silicon is characterized by the apparent absence of However, indiffusion for the experimental conditions studied. outdiffusion is rapid at low concentrations for anneal temperatures of 11 00°C and above. This behavior is qualitatively similar to that reported for fluorine in silicon at lower temperatures.

1. INTRODUCTION Little is known about the diffusion of chlorine in crystalline silicon. Delfino and Lunnon [1] report very little diffusion of chlorine implanted at 67 keV as BCI+ and annealed for 30 m at 9000 C. The present study uses neutron activation/accelerator mass spectroscopy [2] (NA/AMS) to produce depth profiles of implanted chlorine before and after annealing. While there is a marked difference between the annealed and asimplanted profiles for an implant dose of 101 3/cm 2 , the chlorine from The diffusion of the higher dose implants is virtually Immobile. implanted chlorine in silicon is characterized by the apparent absence of However, indiffusion for the experimental conditions studied. outdiffusion is rapid at low concentrations for anneal temperatures of 11 000C and above. This behavior is qualitatively similar to that reported for fluorine in silicon at lower temperatures [3]. 275

Mat. Res. Soc. Symp. Proc. Vol. 354 01995 Materials Research Society

The experimental procedures are detailed in Section 2 and the results are presented in Section 3. The results are discussed in Section 4. 2. EXPERIMENTAL PROCEDURES Single-crystal silicon wafers were used for this study. One set (EK) was provided by T. Z. Hossain, formerly at Eastman Kodak Company. They were implanted with 200 keV 3 5CI by IICO. The implants were made through a 0.06 gim layer of thermally grown Si0 2 at a tilt angle of 70. The second set of implanted wafers was provided by J. F. Ziegler of IBM Research, Yorktown Heights, NY and was designed to extend the Cl dose and energy coverage. The 3 5 CI implants were done at a rotation angle of 22.50 from the axis and at a tilt angle of 70. The implant energies of the 3SCI were 200 and 400 keV. The implanted wafers were sawed into square samples 5 mm on a side and irradiated with thermal neutrons at either SUNY Buffalo or the University of Missouri. The low implant doses (1013 and 5 x 101 3/cm 2 ) were irradiated for 50 hours and the higher doses for 10 hours. A thermal neutron flux of 3 x 101 3 neutrons/cm 2 /s and an irradiation time of