Tsc measurements of coupled levels in ion implanted Si

Thermally Stimulated Current (TSC) measurements have been made on deep states in ion implanted silicon. The nature of the resulting curves and the relationship of the peak to valley transition currents clearly preclude the conventional analysis based on independent emission to the valence band. The results have been analyzed with a model based on coupled levels with interlevel transitions and the fit yields reasonable energy levels and exponential pre-factors. The measurements were made by using shallow n⁺ guard ring diodes implanted with a low dose (3×10¹³ ions/cm²) of 1 MeV B⁺ ions and annealed at 350‡C for one hour. The energy was selected so that the end of the ion track would be in the depletion region of the diodes.