Manufacturability and robust design of nanoelectronic logic circuits based on resonant tunnelling diodes
In: International journal of circuit theory and applications, Jg. Vol. 28 (2000) ; Heft 6, S. 537 - 552
Zeitschriftenaufsatz / Fach: Elektrotechnik
The manufacturability of logic circuits based on quantum tunnelling devices, namely double-barrier resonant tunnelling diodes (RTD), is studied in detail. The homogeneity and reproducibility of III/V mesa technology-based devices is experimentally evaluated and interpreted using multiple I-V characteristic simulations. The experimental sensitivity of the RTD I-V parameters on well and barrier thickness is compared cd with multiple I-V simulations. With shrinking minimum feature size the fluctuations in the peak current can be directly attributed to an RTD area variation caused by the increasing impact of lithography and etching on lateral dimensions. These results prove that the III/V technology fulfils the requirements for a large scale integration of RTD devices. A nanoelectronic circuit architecture based on an improved MOBILE threshold logic gate is presented. Detailed SPICE simulations using the experimental data show that clock and supply voltage fluctuations are tolerated up to +/-0.1 V at a supply voltage of 0.7 V. Very strong local peak voltage variations of 15 per cent in opposite directions would be necessary to have a critical impact on to the circuit Functionality. Smaller deviations only affect the timing without degrading the reliability of the circuit. Consequently, the design of a stable power supply and clocking scheme is more important for the overall circuit performance than the small relative deviations of the RTD peak voltage.