Significance of blackbody radiation in deep-level transient spectroscopy

Deep-level transient spectroscopy has been combined with ion implantation in low-temperature investigations of deep centers in silicon. We demonstrate that thermal radiation, originating from vacuum chamber walls, can influence in situ recording of emission rates significantly. As an example, the emissivity (e(n)) of the hydrogen E3' center was found to be dominated by an optical contribution at temperatures below approximate to 65 K. A typical value, e(n)(op)approximate to 5.5 s(-1), has been recorded in measurements with unshielded Au Schottky diodes. This effect of thermal radiation vanishes when a diode is fully encapsulated and thereby in thermal equilibrium with the radiation field. The optically induced emissivity is particularly large for the hydrogen center used here to illustrate the effect but has been observed for other deep centers as well. (C) 1996 American Institute of Physics.