Study on anti-ambipolar electrical devices and their applications

Abstract

With the advent of the Fourth Industrial Revolution, artificial intelligence (AI) and the Internet of Things (IoT) are becoming the core of new technological innovation. Accordingly, as the number of required electronic devices increases exponentially and data throughput increases, energy consumption in the information and communication technology (ICT) field is expected to increase explosively. Now that Moore's Law has reached its limit, the ternary logic system is drawing attention as one of the ways to meet future energy demands. Ternary logic is considered as a low-power system that can process more information with fewer devices and shorter wiring connections than binary logic. However, depending on the concepts of configuring the ternary logic circuit, the increase of the number of transistors and length of interconnect, or a large loss in static power occurs. To compensate for this, a single pole triple throw (SPTT) concept and an anti-bipolar logic device can be used to reduce the number of devices required and to dramatically prevent static power consumption. The anti-ambipolar logic device that exhibits opposite characteristics of a bipolar device operates in a peak shape only in a specific electric field region. To make use of components for the ternary circuit, various anti-bipolar devices have been surveyed, but it is hard to find the proper anti-ambipolar device for application circuits due to their low performance and limitations on large-area process. In this paper, an anti-ambipolar logic device showing excellent electrical performance, large area process possibility, and low process temperature was implemented and analyzed. Firstly, ZnO and DNTT satisfying the requirements were selected as the constituent semiconductor materials of n-type and p-type, respectively. The two materials were partially overlapped to form heterojunction as an anti-ambipolar device, and excellent electrical properties were obtained with a peak current density of 5.6 nA/μm and a PVR of 106. In addition, by controlling the thickness of each semiconductor channel and introducing charge injection spacer (CIS), device parameters such as peak width and peak position were controllable that gives flexibility for various circuit applications. Using this, the ZnO-DNTT anti-ambipolar device was made use of the SPTT ternary inverter, showing three clear and distinct states, and recording a high voltage gain of 10.3. Above all things, a ternary circuit that requires few devices and consumes 1/1000 of the electrostatic power compared to the saturated current-based ternary logic system was implemented. Finally, the PSpice device modeling was conducted to explore the future development potential of the promising device.