METAL (COSI2) INSULATOR (CAF2) HOT-ELECTRON TRANSISTOR FABRICATED BY ELECTRON-BEAM LITHOGRAPHY ON A SI SUBSTRATE/

We fabricated a small-area metal (CoSi2)/insulator (CaF2) hot electron transistor using electron-beam lithography. The transistor is compose d of a CoSi2/CaF2(1.9 nm)/CoSi2(1.9 nm) tunnel emitter and a CaF2(5 nm ) collector barrier on an n-Si(111) substrate. The emitter mesa area i s 0.9 x 0.9 mu m(2). Although the measured characteristics show, for t he first time, clear transistor action with a curve similar to those o f semiconductor HETs: the collector current increases without saturati on due to leakage current through the SiO2 film under the external ele ctrode pads. The intrinsic device characteristics (zero leakage curren t) exhibited saturation, and a current gain beta greater than or equal to 36 was obtained at 77 K.