Simulation of transient enhanced diffusion of B in Si

Gyeong S. Hwang, Eugene Heifets, Tahir Cagin, and William A. Goddard III

Materials and Process Simulation Center, Beckman Institute (139-74)

California Institute of Technology, Pasadena, CA 91125

Yuzuru Sato and Masamitsu Uehara

Seiko Epson Corp., Japan


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

We present a systematic approach to address such issues in which we combine

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+ ion implants into MBE-grown B-doped layers, where dopant concentrations are mostly less than 1018 cm-3. The dominant mechanisms of the B TED based on this previous work may not be dominant for the low energy (< 1 keV) implantation and high dopant concentration (> 1019 cm-3) inherent to ultrashallow junction fabrication. Our kinetic MC simulations show several interesting features in the low-energy and high-concentration regime:

  1. the "+1" model is no longer valid,
  2. the surface effect is insignificant, and
  3. small clustering of defects and dopants plays an important role in determining junction profiles.

We will also present results on strain-induced defect-defect interactions and discuss how crucial it is to have such detailed information for accurately predicting the doping profiles in ultrashallow junction processing.