Regrowth of Implanted-Amorphous Si: Furnace to Laser Annealing

Abstract

High-quality, epitaxial layers regrown from ion-implanted, amorphous Si are an important element in integrated circuit fabrication. Two regimes are well-characterized and understood: furnace annealing in the solid phase from 500° to 1000°C and pulsed-laser annealing in the liquid-phase. Growth rates have been measured in the range from 1 Å/sec in the solid phase to 10 m/sec in the liquid phase. Impurity redistribution is in hand and only the strong enhancement of solid phase rates due to the presence of 0.1 at. % or greater of dopants remains as a controversial issue.

The emergence of rapid thermal annealing (10 to 20 sec at 1000 to 1100°C) as an attractive method of restoring crystal order has introduced a new area of controversy; in this case, growth rates and impurity redistribution. The experimental data from several groups will be presented in order to highlight the different mechanisms that have been invoked. The redistribution of implanted B and As will also be discussed.