Thermal ionization rates and energies of holes at the double acceptor zinc centers in silicon

The thermal emission rates and activation energies of holes trapped at the neutral and singly ionized zinc centers are measured using the dark capacitance and current transient techniques in n+–p junctions. The thermal activation energies of holes from these centers are 316 and 617 meV, respectively. Detailed electric field dependences of the thermal emission rates are obtained using a differential bias voltage technique. The thermal emission rate of holes from neutral zinc centers exhibits a very large field dependence, while that from singly ionized zinc centers is small. A second zinc-related center, which is attributed to the previously reported acceptorlike, zinc–-boron complex, is studied. The thermal activation energy of trapped holes from this center is 167 meV.