REVERSIBLE CHANGES OF THE CHARGE-STATE OF DONOR HYDROGEN COMPLEXES INITIATED BY HOLE CAPTURE IN SILICON

The effect of light-injected holes on phosphorus/hydrogen-pairs has been examined in silicon. Previous studies have shown that light soaking appears to debond H from phosphorus, thereby returning it to the positive charge state. Here, we demonstrate that this charge state change is partially reversible if samples are held in electronic equilibrium for periods of hours to days. Since this recovery process can be delayed for days by depleting the light-soaked region, it appears that freed hydrogen is not merely returning to donors, but that the original hole capture event is merely creating a different charge state of the P.H pair. We also demonstrate that the kinetics of the hole-induced conversion process is markedly different in depletion than in zero bias and suggest that this is due to the presence of the recovery process which can only occur in the presence of free electrons.