A note on trap recombination in high voltage device structures

The carrier lifetime is a very important parameter influencing all important characteristics of bipolar devices both discrete and integrated structures and carrier lifetime tailoring is an important part of power semiconductor device technology. In presented paper, recombination through traps (centres with a deep energy level between edge of bandgap and Fermi level) is discussed in more details. It has been shown that some traps can considerably influence recombination rate in silicon, and that at some traps a considerable temperature dependence of the centre cross-sections may be found. This is demonstrated in the case of iridium traps with a deep energy level 0.28 eV below the conduction band which capture cross-section temperature dependence has been found σ_p ∝ T⁴ and σ_n ∝ T⁴. Further, the problem on low injection carrier lifetime in low-doped layers of high voltage semiconductor devices is also discussed.