Tunable Negative Differential Resistance in MISIM Tunnel Diodes Structure With Concentric Circular Electrodes Controlled by Designed Substrate Bias

Abstract

The tunable negative differential resistance (NDR) characteristics of metal–insulator–semiconductor–insulator–metal (MISIM) tunnel diodes (TDs) structure with thin oxide were observed by biasing the substrate simultaneously with one of the TDs under designed voltage drops ( $\Delta \text{V}$ ). An inner circular electrode TD surrounded by a ring-shape electrode TD gate pattern was adopted. The NDR region can be adjusted by varying the $\Delta \text{V}$ between the inner TD and the body. Not only the peak-to-valley current ratio (PVCR) but also the voltage range where NDR occurs can be controlled. It is supposed that the injected electrons and the inversion charges increase and decrease with negative bias, respectively, for the MIS(p) TD and play an important role in this observation. Meanwhile, the asymmetry of inner gate and ring gate enhances the coupling efficiency at reverse bias region. In this paper, the PVCR can be tuned to more than two orders and the voltage of the NDR region can be shifted to larger than 1 V. The tunable NDR characteristic of MISIM provides a possible application of MIS TD.