Electrical Activation of Implanted Arsenic in Silicon during Low Temperature Anneal

Abstract

The correlation between the electrical activation of implanted As in Si and the recrystallization of the amorphous layers during low temperature anneals at 440°–650°C is studied by Hall effect measurements and glancing incidence channeling analysis. The results show that the activation process is described well by a simple epitaxial regrowth model. Implanted As atoms are electrically activated during the recrystallization with an activation energy ∼2.7 eV. The electrical activation depends strongly on the crystal orientation of the wafer. In (100) oriented wafers the activation rate is highest, and we can achieve almost complete activity. However, in (110) and (111) oriented wafers, about 20 and 35% of As atoms are unactivated, respectively. It is confirmed from channeling analysis that lattice disorder remains in (110) and (111) oriented wafers. It is speculated that these defects act possibly as carrier compensating centers, thereby reducing the electrical activity.