DEPENDENCE OF GATE CONTROL ON THE ASPECT RATIO IN METAL METAL-OXIDE/METAL TUNNEL TRANSISTORS/

The design criteria for large transconductance/high output impedance o r high-gain operation of metal-oxide tunneling transistors is given. T he dependence of the gate control on the aspect ratio of thickness to width of the tunneling oxide is investigated by computer simulation. T his device structure can only operate similar to conventional semicond uctor transistors for aspect ratio considerably less than one. It ceas es to function as a transistor for larger aspect ratio due to insuffic ient penetration of the gate control field into the tunneling oxide. T o demonstrate this, the current-voltage characteristics are computed f or aspect ratios equal to 7/30, 1, 21/10, and the different tunneling- current behaviors compared with our experimental results on Ti/TiOx/Ti and Nb/NbOx/Nb tunnel transistors. [S0021-8979(98)01114-1].