Thermal emission rates and capture cross sections of majority carriers at vanadium centers in silicon

Abstract

The thermal emission rates and capture cross sections of majority carriers on the vandium associated centers in the depletion region of reverse biased silicon p- n junctions have been measured by the dark capacitance transient method. The three vanduim associated levels observed, two donor levels and a deep acceptor level, belong to the same vandium center. Least square fits of the emission data give the following emission rates; e nl t = 1.047 × 10 6T 2 exp [−0.179±0.004 eV/kT], e n0 t = 3.55 × 10 7T 2 exp [−0.426±0.004 eV/kT] and e p-2 t = 1.514 × 10 6T 2 exp [−0.450±0.003 eV/kT]. The activation energy of the hole emission rate at the lower donor level is about 0.1 eV larger than the equilibrium thermal activation energy. The capture cross sections are σ n0 = 3 × 10 −17 cm 2 and σ p0 = 8 × 10 −16 cm 2 for the electron capture process at the deep acceptor level and the hole capture process at the upper donor level, respectively. The hole capture cross section on the lower donor level ( σ p-1 ) depends significantly on temperature. The large temperature dependence of the hole capture cross section can be expected due to the nonradiative multiphonon emission process.