Low-voltage operation from the tower structure metal–oxide–semiconductor field-effect transistor Si field emitter

To improve emission stability and realize low turn-on voltage, a silicon field emitter controlled by a metal–oxide–semiconductor field effect transistor (MOSFET) was fabricated and demonstrated. The emitter cathode was fabricated in the n-well drain of the MOSFET on a p-type silicon substrate. In addition to the extraction gate, another electrode was introduced as the MOSFET’s control gate. This gate’s oxide thickness was designed to be thinner than that of the extraction gate for low turn-on voltage. Furthermore, two types of drain structure were adopted to compare device reliability with regard to impact ionization effect. Experimental results showed that emission current was effectively controlled by the MOSFET at a gate voltage of less than 5 V. It was found that impact ionization was caused near the drain edge, where a high electric field was concentrated, in the conventional drain structure. Consequently, MOSFET characteristics were significantly influenced.