Arsenic deactivation in silicon

摘要

In this paper we examine the properties of arsenic in silicon, using ab initio calculations and a statistical theory. Good agreement is found between theory and experiment for the electronic concentration as a function of temperautre and total arsenic concentration. We show that for low arsenic concentrations, full activation is the equilibrium condition. In equilibrium, the neutral complex composed of a lattice vacancy surrounded by four arsenic (VAs_4) is the dominant means by which high concentrations of arsenic are rendered inactive. Under constrained equilibrium conditions in which VAs_4 cluster formation is prohibited, we show that VAs_3Si_1 cluster populations increase dramatically and can account for nearly the same degree of compensation as the VAs_4 clusters. Even VAs_2 clusters alone can account for substantial deactivation in the absence of VAs_4 clusters. These smaller complexes are essential not only to the establishment of equilibrium, since SiAs_4 clusters are extremely rare, but can also explain some degree of deactivation, even if the formation of VAs_4 clusters are kinetically inhibited.