Vertical integration of structured resonant tunneling diodes on InP for multi-valued memory applications

The authors report vertical integration of AlAs/InGaAs/InAs/InGaAs/AlAs resonant tunneling diode (RTD) structures on InP; as many as 15 have been grown in series combination. They show that hysteresis in the current-voltage characteristics caused by series resistance can be reduced by doping the resonant tunneling double barrier structures, and further reduction in hysteresis is possible through structural modifications. The doped RTDs have reduced resonance voltage with approximately equal peak spacings and good peak-to-valley ratios. Using an FET as a constant current load with an 8-peak vertically integrated RTD device, a nine-state multivalued memory is demonstrated.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>