Hydrogen-induced dissociation of the Fe-B pair in boron-doped p-type silicon

The interaction between hydrogen and the iron-boron pair (Fe-B) has been investigated in iron-contaminated boron-doped Cz-Si using capacitance-voltage measurements (CV) and deep level transient spectroscopy (DLTS). Introduction of hydrogen was performed by wet chemical etching and subsequent reverie bias annealing of Al Schottky diodes. The treatment led to the appearance of the defect level characteristic to interstitial iron (Fe-i) with a corresponding decrease in the concentration of the Fe-B pair. Concentration versus depth profiles of the defects show that dissociation of Fe-B occurs in the depletion region and capacitance-voltage measurements unveil a decrease in the charge carrier concentration due to passivation of B. These quantitative observations imply strongly that H promotes dissociation of Fe-B releasing Fe-i whereas no detectable passivation of Fe-B or Fe-i by H occurs.