Wigner-Poisson simulation of memory switching heterostructure tunneling diodes

GaAs/AlAs double barrier diodes incorporating n/sup -n/sup +n/sup -/ spacer layers can exhibit memory switching behavior. Such devices can be reversibly switched between two conduction branches and retain memory of the branch last switched to even after short circuit conditions. We model this memory switching phenomenon using a quantum kinetic formulation based on the Wigner function. The numerical model is based on an improved 4-point difference scheme that allows control of numerical dissipation. For the devices discussed, the calculations result in two states at zero bias. Associated with each state is a distinct and stable conduction branch. This work is a step towards understanding the more complex aspects of the phenomenon, such as branch switching when the device is driven far from equilibrium.<>