A power junction gate field-effect transistor structure with high blocking gain

Abstract

A new gate structure is described for vertical-channel power junction gate field-effect transistors (FET's). This gate structure has vertically walled gate regions extending perpendicular to the wafer surface. The structure is fabricated by using orientation-dependent silicon etching and selective vapor-phase epitaxial refill techniques. In comparison to previous gate structures made by planar diffusion, the vertically walled gate structure exhibits one order of magnitude improvement in blocking gain. This improvement in blocking gain has allowed the fabrication of devices having breakdown voltages above 400 V and a current-handling capability of more than 0.5 A with an on-resistance of 12 Ω. The devices are designed to exhibit pentode-like characteristics at low gate voltages and triode-like characteristics at large reverse gate bias voltages in order to obtain the observed high-power handling capability.