Origin Of Negative Capacitance Research Articles

Progress and future prospects of negative capacitance electronics: A materials perspective

Negative capacitance in ferroelectric materials has been suggested as a solution to reduce the power dissipation of electronics beyond fundamental limits. The discovery of ferroelectricity and negative capacitance in the widely used class of HfO2-based materials has since sparked large research efforts to utilize these effects in ultra-low power transistors. While significant progress has been made in the basic understanding of ferroelectric negative capacitance in recent years, the development of practical devices has seen limited success so far. Here, we present a unique view of the field of negative capacitance electronics from the ferroelectric materials perspective. Starting from the basic principles of ferroelectric negative capacitance, we discuss the desirable characteristics of a negative capacitance material, concluding that HfO2-based ferroelectrics are currently most promising for applications in electronics. However, we emphasize that material non-idealities can complicate and in some cases even inhibit the design and fabrication of practical negative capacitance devices using HfO2-based ferroelectrics. Finally, we review the recent progress on experimental devices and give an outlook on the future direction of the field. In particular, further investigations of the microscopic structure of HfO2-based ferroelectrics are needed to provide an insight into the origin of negative capacitance in this material system and to enable predictive device design.

Microelectronic properties of the organic Schottky diode with pyronin-Y: Admittance spectroscopy, and negative capacitance

The Au/Pyronin-Y/p-Si/Al Schottky diode was designed and studied by using the DC and AC measurements. Current-voltage (I-V), capacitance-voltage (C-V) and conductance-voltage methods under different frequencies and voltage biasing were measured at room temperature. The I-V characteristics and C-V characteristics were determined by using the electrical and impedance measurements. From I-V characteristics curve, the Au/pyronin-Y/p-Si/Al Schottky diode has a rectifying behavior. The parameters of Schottky diode such as the series resistance, ideality factor, and barrier height were computed for Au/Pyronin-Y/p-Si/Al junction diode. The performance of the Au/pyronin-Y/p-Si/Al diode is attributed to the creation of the interfacial layer by the organic semiconductor dye. Admittance spectroscopy method can describe the series resistance-voltage (Rs-V) and impedance-voltage (Z-V), capacitance-voltage (C-V) and conductance-voltage (G-V) measurements at different frequencies at room temperature. This device showed a negative capacitance at higher frequencies. The origin of negative capacitance is attributed to the inductive behavior of the studied materials. From C-V analysis, different parameters were calculated and analyzed such as the doping concentration, the built-in potential, the depletion layer and the diffusing potential at zero bias. The obtained results support that the electronic properties of the silicon-based Schottky diode can be controlled by the interlayer organic layer (Pyronin-Y).

The origin of negative capacitance in Au/n-GaAs Schottky barrier diodes (SBDs) prepared by photolithography technique in the wide frequency range

Capacitance–voltage (C–V) and conductance–voltage (G/ω–V) measurements of the Au/n-GaAs Schottky barrier diodes (SBDs) in the wide frequency range of 10 kHz–10 MHz at room temperature were carried out in order to evaluate the reason of negative capacitance (NC). Experimental results show that C and G/ω are strong functions of frequency and bias voltage especially in the accumulation region. NC behavior was observed in the C–V plot for each frequency and the magnitude of absolute value of C increases with decreasing frequency in the forward bias region. Contrary to C, G/ω increases with decreasing frequency positively in this region. NC behavior may be explained by considering the loss of interface charges at occupied states below Fermi level due to impact ionization processes. Such behavior of the C and G/ω values can also be attributed to the increase in the polarization especially at low frequencies and the introduction of more carriers in the structure. The values of Rs decrease exponentially with increasing frequency according to literature. In addition, the values of C and G/ω at 1 MHz were corrected to obtain the real diode capacitance by taking the effect of Rs into account.