A study of electrical characteristics improvements in sub-0.1 mu m gate length MOSFETs by low temperature operation

MOSFETs with sub-0.1 mu m gate length were fabricated, and their low temper ature operation was investigated. The drain current for drain voltage of 2 V increased monotonously as temperature was lowered to 15 K without an infl uence of the freeze-out effect. Moreover, the increase in the drain current was enhanced by the gate length reduction. The hot-carrier effect at low t emperature was also investigated. Impact-ionization decreased as temperatur e was lowered under the condition of drain voltage less than or equal to 2 V. The decreasing ratio was enhanced as gate length became shorter. We cons ider this phenomenon is attributed to the non-steady-stationary effect. As a result, device degradation by DC stressing was reduced at 77 K in compari son with room temperature. In the case of 0.1 mu m MOSFET, drain current wa s not degraded in condition of DC stress with gate- and drain-voltage was 1 .5 V.