Control of current polarity in concentric metal–insulator-semiconductor tunnel diode (MISTD) structures by designed coupling rings

In this paper, the coupling effect within the concentric metal–insulator- semiconductor tunnel diodes (MISTDs) is proposed. By adjusting the voltage of rings, different polarities of center current can be obtained. Additionally, a multilevel characteristic in current output is achieved through varying ring quantities. The mechanism behind the phenomenon of current polarity reversal is attributed to the interplay between the coupling current among the MISTDs and the tunneling current. When adjacent MISTDs apply different biases, the electric field leads to carriers’ motion, resulting in coupling currents with different polarities. On the other hand, the voltage applies to the center gate induces tunneling current. These two types of currents determine the output current polarity. Furthermore, 2-D TCAD simulation was conducted, demonstrating the alignment of the simulated current trends with experimental results. Confirmation of the coupling current assumption was achieved through electron concentration and electron current density, validating the accuracy of the described mechanism. Finally, based on this coupling effect, different logic functions can be achieved by adjusting the voltages of the surrounding rings and the center. The 1/0 logic states can be defined through the different current polarities, while maintaining extremely low power density.