AVS 47th International Symposium
    Manufacturing Science and Technology Thursday Sessions
       Session MS-ThM

Paper MS-ThM1
Simulation of Transient Enhanced Diffusion of B in Si

Thursday, October 5, 2000, 8:20 am, Room 304

Session: Advanced Modeling and Control for IC Manufacturing
Presenter: G.S. Hwang, California Institute of Technology
Authors: G.S. Hwang, California Institute of Technology
W.A. Goddard III, California Institute of Technology
Correspondent: Click to Email
Ever shrinking device dimensions requires the formation of ultrashallow junctions with high concentrations of electrically active dopants and box-like profiles in order to maximize drive currents while minimizing short channel effects. To control such junction properties it is necessary to understand quantitatively (i) the underlying mechanisms of transient enhanced diffusion (TED) of dopants and (ii) the dynamics of defect/dopant clustering during implantation and postimplantation annealing. We present a systematic approach to address such issues in which we combine (i) kinetic Monte Carlo (kMC) mesoscale simulations capable of describing the length and time scales of TED with (ii) quantum mechanics [density functional theory (DFT)] calculations of the fundamental atomic level processes and (iii) experimental validation. In recent years much effort has been devoted to understanding the TED of B in Si; however, most studies have been performed using moderate energy (~40 keV) Si@super +@ implants into MBE-grown B-doped layers. The dominant mechanisms of the B TED based on this previous work may not be dominant for the low energy (<1 keV) B@super +@ implantation and high dopant concentration (>10@super 20@ cm@super -3@) inherent to ultrashallow junction fabrication. In this talk, we will present (i) new mechanisms of B clustering and (ii) strain-induced defect-defect and defect-dopant interactions, and discuss how crucial it is to have such detailed information for accurately predicting the doping profiles in ultrashallow junction processing. We will also address several unresolved issues in the low-energy and high-concentration regime: (i) the validity of '+1' model, (ii) the surface proximity effect, and (iii) the role of defect/dopant clustering in determining junction profiles.