The Role of Charge and Recombination-Enhanced Defect Reaction Effects in the Dissociation of FeB Pairs in p-Type Silicon under Carrier Injection

The dissociation of FeB pairs in p-type silicon under injection is often explained by the charge state change of interstitial Fe (Fe_i) from positive to neutral. It is also sometimes interpreted as a recombination-enhanced defect reaction (REDR) mechanism. The charge effect and the REDR have fundamentally different impacts on the dissociation/association reactions: the former changes the concentration of Fe_i⁺, whereas the latter changes the reaction rate constants. Herein, the two effects are investigated and compared through measuring and analyzing the dynamics of the reactions. The results confirm that the dissociation of FeB under carrier injection cannot be purely attributed to the change of charge states. The extracted dissociation/association rate constant ratio shows an approximately linear dependence on the recombination rate on each FeB pair, indicating the REDR effect. The results allow the two effects to be directly compared, highlighting the dominant role of the REDR effect in dissociating the pairs.