Transistor characteristics of 14-nm-gate-length EJ-MOSFETs

We have fabricated electrically variable shallow junction metal-oxide-silicon field-effect transistors (EJ-MOSFETs) to investigate transport characteristics of ultrafine gate MOSFETs. By using EB direct writing on an ultrahigh-resolution negative resist (calixarene), we could achieved a gate length of only 14 nm. Despite such an ultrafine gate, the device exhibited transistor operation at room temperature. From studying the devices with the gate lengths from 14 nm to 98 nm, we found that when the gate length was below 30 nm the subthreshold leakage current increased. The low-temperature measurements showed that the leakage current was caused by the classical thermal process and that quantum effects do not play an important role in subthreshold characteristics at room temperature.