A NEW VOLTAGE TRANSIENT TECHNIQUE FOR DEEP-LEVEL STUDIES IN DEPLETION-MODE FIELD-EFFECT TRANSISTORS

A new variation of deep-level transient spectroscopy, suitable for dep letion-mode field-effect transistors, is presented. It is similar to t he conductance deep-level transient spectroscopy but does not require simultaneous measurement of the transconductance or the mobility for c alculation of the trap concentrations. It is also independent of the t ransistor size and is very sensitive. The technique is demonstrated wi th measurements of radiation-induced traps in buried channel metal-oxi de-semiconductor field-effect transistors which are used as output amp lifiers in char ge-coupled device imagers. The unique structure of the se transistors offers extended opportunities for studying the space di stribution of the radiation-induced defects. In addition, we show a va riation of the new transient technique using back-gate driving, which is applicable for studying the channel-substrate p-n junction, and the results are compared with those obtained from constant-capacitance vo ltage-transient measurements. Complementary measurements using front-g ate and back-gate operation of the new technique can help to resolve t he ambiguities usually associated with deep-level transient spectrosco py measurements of symmetrical p-n diodes.