MULTIPLE-VALUED PROGRAMMABLE LOGIC ARRAY BASED ON A RESONANT-TUNNELING DIODE MODEL

Toward the age of ultra-high-density digital ULSI systems, the develop ment of new integrated circuits suitable for an ultimately fine geomet ry feature size will be an important issue. Resonant-tunneling (RT) di odes and transistors based on quantum effects in deep submicron geomet ry are such kinds of key devices in the next-generation ULSI systems. From this point of view, there has been considerable interests in RT d iodes and transistors as functional devices for circuit applications. Especially, it has been recognized that RT functional devices with mul tiple peaks in the current-voltage (I-V) characteristic are inherently suitable for implementing multiple-valued circuits such as a multiple -state memory cell. However, very few types of the other multiple-valu ed logic circuits have been reported so far using RT devices. In this paper, a new multiple-valued programmable logic array (MVPLA) based on RT devices is proposed for the next-generation ULSI-oriented hardware implementation. The proposed MVPLA consists of 3 basic building block s: a universal literal circuit, an AND circuit and a linear summation circuit. The universal literal circuit can be directly designed by the combination of the RT diodes with one peak in the I-V characteristic, which is programmable by adjusting the width of quantum well in each RT device. The other basic building blocks can be also designed easily using the wired logic or current-mode wired summation. As a result, a high-density RT-diode-based MVPLA superior to the corresponding binar y implementation can be realized. The device-model-based design method proposed in this paper is discussed using static characteristics of t ypical RT diode models.