GeSi/Si bistable diode exhibiting a large on/off conductance ratio

A novel bistable phenomenon having both a high conductance on state and a high impedance off state has been observed in a forward biased delta-doped GeSi/Si tunnel diode grown by molecular beam epitaxy. The bistable characteristics are attributed to the different mobile carrier densities in the delta-doped layers, which leads to the switching of the band structure from a tunnel junctionlike alignment to a p-i-n junctionlike alignment or vice-versa. An on/off conductance ratio larger than 10⁶ has been demonstrated for a modified diode structure. The device processing is technologically compatible to the current Si metal-oxide-semiconductor technology, making the device useful for a high speed, high density static random access memory cell.