The Local Structure of Antimony in High Dose Antimony Implants in Silicon by XAFS and SIMS.
- PDF / 216,204 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 75 Downloads / 192 Views
The Local Structure of Antimony in High Dose Antimony Implants in Silicon by XAFS and SIMS. M. Alper Sahiner1, Steven W. Novak1, Joe C. Woicik2, Yayoi Takamura3, Peter B. Griffin3, James D. Plummer3 1
Evans East, East Windsor, New Jersey 08520 National Institute of Standards and Technology, Gaithersburg, Maryland 20899 3 Center for Integrated Systems, Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305 2
ABSTRACT One of the important challenges in semiconductor industry is to sustain high concentration of dopant atoms electrically active in very small areas. In investigating the optimum post implantation treatment methods that will help to attain these conditions, the local structural information around the dopant atom is crucial. In this study, we have used secondary ion mass spectroscopy (SIMS) and xray absorption fine structure spectroscopy (XAFS) to obtain the concentration depth profiles and the local structural information around the Sb atom in laser thermal annealed (LTA) Sb implants in Si wafers. The Sb implant doses used in this work are 6.4x1015/cm2 and 2.0x1016/cm2. The XAFS results for the 6.4x1015/cm2 Sb dose sample do not exhibit any rhombohedral-Sb precipitation as the Fourier Transformed (FT) data can be fit successfully using only substitutional-Sb in the Si lattice sites. However, a multi-shell analysis of the Fourier Transformed (FT) data for the 2.0x1016/cm2 Sb dose sample clearly indicates there is a substantial contribution from the Sb-Sb scattering, which is a signature of precipitated form of Sb. INTRODUCTION Doping intrinsic Si with n or p-type dopant atoms above the solid solubility limits to increase the charge carrier concentration, and sustaining high level carrier concentration by eliminating any inactive structures (clusters or precipitates) in terms of annealing mechanisms is one of the main challenges of the semiconductor industry. Information on the local structure around the impurity atom is of crucial importance to face with these requirements. XAFS, being capable of probing the short range order in crystalline and amorphous materials provides information on the coordination number, near-neighbor distances around the impurity atom. This information can be used to identify the nature and amount of dopant-related inactive structures in the material. In reducing the number of these inactive structures in high dose implants in Si, laser annealing (LA) is one of the important post implantation techniques. Laser annealing has been shown to be very useful in repairing the damage to the crystal due to implantation and recovering the active carrier concentration in many systems[1]. In this study, Sb implanted Si wafers at two different doses were laser annealed and subsequently the local structure around the Sb atom was probed by XAFS. The Sb doses for this study are 6.4x1015 atoms/cm3 (will be referred as the low dose) and 2.0x1016 atoms/cm3 (will be referred as the high dose). The high dose sample was subjected to further thermal annealing after LA. Sb doping in
Data Loading...
