Gated resonant tunnelling devices

The fabrication and operation of a 1 mu m*1 mu m gated GaAs-(AlGa)As resonant tunnelling diode is described. By biasing the gate, the I/V characteristic can be varied and hence the negative differential resistance of the diode can be controlled. Using a wafer with an appropriate doping profile ensures that the maximum depletion due to the gate will occur close to the (AlGa)As tunnel barriers. When a large negative bias is applied to the gate extra structure develops in the I/V characteristic which may be related to the modification of the sub-band structure in the well due to the lateral quantum confinement of electrons by the gate. The potential of this fabrication technique is also discussed for resonant tunnelling and vertical field effect transistors.