A permeable-base switching device using stacked layers of silicon, silicon dioxide, and silicon-rich silicon dioxide

A novel permeable-base device that is a type of solid-state analog to the vacuum tube has been-constructed using stacked layers of silicon, silicon dioxide, and silicon-rich silicon dioxide. The base or grid, which is formed from thin patterned polycrystalline silicon with degenerate doping, is separated from a single-crystal silicon substrate that acts as the collector or anode by a layer of silicon dioxide. The emitter or cathode is formed on top of the base using a stack of silicon dioxide, silicon-rich silicon dioxide, and degenerately doped polcrystalline silicon (known as an electron injector structure). Current flow from the emitter to the base and collector is modulated by the electric fields created in the silicon dioxide layers by the voltages applied to the various terminals. This unipolar device, which has only electrons carrying the current, is shown to be capable of operation over a wide range of voltages and gains depending on design.