Рекомбинация носителей заряда через возбужденные уровни бора в кремнии при низких температурах

Abstract

In present article was studied the process of recombination of charged carriers across shallow impurity boron’s centers in silicon at low temperatures. Major attention was devoted to theoretical interpretation of empiric temperature dependencies of lifetime τ(T) of the carriers in the temperature range of (1.7 – 4.2) K under doped impurity concentrations nB ≥ 1014 sm – 3 with compensation ≤ 10% (nD + nA ≤ 1013 sm – 3). It is enough exactly determined that shallow excited level with binding energy 5 meV (3s-state) is almost resonant. The approximate formulas for the coefficient of resonant capture are obtained. Influence of weak magnetic field (10 – 100) Gs on value of the coefficient of resonant capture is analyzed, as for showed that weak magnetic field (in order 10 Gs) loosely decreases of carrier’s lifetime in such a way to stimulate a process of their recombination.