Semiconductor diodes having low forward conduction voltage drop, low reverse current leakage, and high avalanche energy capability

Abstract

Semiconductor diodes are diode connected cylindrical field effect transistors having one diode terminal as the common connection between the gate and the drain of the cylindrical field effect transistors. The method of processing the field effect transistor provides very short channels, shallow diffused regions and trench terminated junctions at the edges of the active device. The trench terminated junctions are formed out of a vertical etch cut through the P-N junction at the edge of the device forming the trench which is then passivated with a dielectric material to provide a region of higher breakdown voltage at the edge of the device than is seen within the active device area. The trench terminated junction results in spreading the breakdown energy over the entire active device region rather than just device edges. The preferred fabrication technique for the active device uses two masks and two masking steps, without any critical mask alignment requirements.