Negative capacitance and negative dielectric behavior of MIS device with Rhenium-Type Schottky contacts

This study offers a thorough examination of the negative capacitance/dielectric behavior of an MIS device with rhenium (Re) type Schottky contact and native oxide interlayer. The pulsed laser deposition method was used to deposit Re as the Schottky contact on the n-type GaAs substrates. Thus, the electrical and dielectric properties were evaluated by I-V, C-V, and G/ω-V tests at a high frequency (1 MHz). Experimental results demonstrated that capacitance characteristics showed a marked increase from the inversion region to depletion, with a localized peak observed at 0.26 V. Exceeding 4.16 V, the capacitance values turn negative, signifying a shift to inductive behavior, as shown by a rapid increase in conductance values under the same conditions. In addition, the dynamic resistance profile indicates that the series resistance (Rs) reaches its peak at near-zero bias and stabilizes under significant forward bias, approaching the device's intrinsic series resistance. Analysis of the C–G/ω–V data also showed two distinct peaks in the corrected conductance (Gc/ω) at –0.55 V and + 0.1 V, due to the response of interface states (Nss) located at distinct energy levels inside the GaAs bandgap. The transition from capacitive to inductive behavior was recorded with high enough forward bias, at which point the dielectric constant (ε′) turns negative, showing the effects of polarization reversal and reactive energy storage. Additionally, the complex impedance analysis revealed distorted semicircular arcs and loop formations, indicative of interfacial inhomogeneities and multiple charge transport channels. As a result, these findings demonstrate that integrating Re into the MIS structure significantly improves the device's electrical stability and functional response under varying bias conditions, demonstrating its potential in advanced high-frequency and low-power electronic applications.