ULTRARAM is a III−V compound semiconductor memory concept that exploits quantum resonant tunneling to achieve nonvolatility at extremely low switching energy per unit area. Prototype devices are fabricated in a 2 × 2 memory array formation on GaAs substrates. The devices show 0/1 state contrast from program/erase (P/E) cycles with 2.5 V pulses of 500-µs duration, a remarkable switching speed for a 20 µm gate length. Memory retention is tested for 8 × 10 4 s, whereby the 0/1 states show adequate

more »

... contrast throughout, whilst performing 8 × 10 4 readout operations. Further reliability is demonstrated via program-read-erase-read endurance cycling for 10 6 cycles with 0/1 contrast. A half-voltage array architecture proposed in our previous work is experimentally realized, with an outstandingly small disturb rate over 10 5 half-voltage cycles. Index Terms-InAs/AlSb, memory, non-volatile memory (NVM), non-volatile RAM (NVRAM), resonant tunneling.