Dissociation of iron-related centers in Si stimulated by hydrogen

The interaction of hydrogen with Fe-related centers in p-type Si was investigated by deep level transient spectroscopy (DLTS). After wet chemical etching (WCE) of iron diffused Si samples the interstitial iron concentration exceeds the equilibrium concentration close to the surface. The iron depth profiles exhibit an exponential dependence with a characteristic length identical to the hydrogen penetration depth, which is about ten times larger than the iron diffusion length. On the other hand, after reverse bias annealing (RBA) the iron profile deviates clearly from the exponential distribution. Our results give evidence for a release of iron by a hydrogen-stimulated dissociation of iron-related defects.