Kinetics of minority-carrier-enhanced dissociation of hydrogen-dopant complexes in semiconductors

The kinetics of minority-carrier-enhanced dissociation of dopant-hydrogen complexes in semiconductors are quantitatively characterized with a new experimental technique. Its principal feature is the ability to control independently the width of the space-charge layer and the flux of minority carriers through the layer. The dissociation kinetics are formulated in terms of a phenomenological cross section for the capture of a minority carrier by a dopant-hydrogen complex. The method is demonstrated with hole-enhanced dissociation of the PH complex in silicon. The capture cross section has a room-temperature value of {~}3×{}10^-19 cm² and is thermally activated with an energy of {~}0.3 eV, as compared to the thermal dissociation energy of 1.2 eV for the PH complex. Possible mechanisms for minority-carrier-enhanced dissociation are evaluated with configuration coordinate diagrams.