Bond-centered hydrogen in silicon studied by in situ deep-level transient spectroscopy

In situ deep level transient spectroscopy (DLTS) has been applied to investigate n-type silicon implanted with protons at low temperatures. Two DLTS signals, labeled E3' and E3 ", originate from hydrogen-related donor centers. The electron emission rates of the donors are similar and the two signals are discernible only because they form and anneal differently. In n-type silicon, the E3' and E3 " centers transform into negatively charged centers at similar to 100 K and less than or similar to 65 K, respectively. Both signals can be regenerated at 65 K: E3' by forward-bias injection of holes and E3 " by illumination with band-gap light under reverse-bias conditions. During the E3' regeneration long-range migration of hydrogen occurs, whereas E3 " regenerates without migration. Tn the space-charge layer of reverse biased diodes, E3 " converts into E3 " with an activation enthalpy of 0.44 eV in oxygen-rich material, whereas E3 " converts into E3' with an activation enthalpy of 0.72 eV in oxygen-poor material-It is found that the density of hydrogen sites associated with E3 " approximately equals the oxygen concentration, whereas the density of E3' sites is about 10(23) cm(-3). These results provide further evidence for our previous assignment of E3' to isolated hydrogen at a bond center site and leads to the assignment of E3 " to bond centered hydrogen perturbed by a nearby oxygen atom. We argue that dilated Si-Si bonds in the strain fields around impurities and defects an trapping sites for hydrogen.[S0163-1829(99)01727-0].