INTERFACE ROUGHNESS SCATTERING IN ALAS INGAAS RESONANT-TUNNELING DIODES WITH AN INAS SUBWELL/

We present simulation results on the current-voltage (I-V) characteris tics of an InP-based AlAs/InGaAs resonant tunneling diode (RTD) with I nAs subwell. Space-charge limited transport is accounted for using a s elf-consistent electrostatic potential calculated using the Hartree ap proximation. Three-dimensional scattering is simulated using the recen tly developed multiple sequential scattering theory. Interface roughne ss scattering is found to be dominant over polar phonon scattering in the devices studied. Of particular interest is interface-roughness (IR ) scattering at the InGaAs/AlAs and InGaAs/InAs interfaces and its imp act on the valley current. The existence of a critical terrace size th at maximizes IR scattering is identified through simulation. The origi n of the asymmetry commonly measured in the RTD I-V characteristic is discussed with respect to asymmetries in interface scattering. The use of the InAs subwell and associated interface roughness scattering to tune the peak current while keeping a nearly constant current peak-to- valley ratio is demonstrated. (C) 1996 American Institute of Physics.