The C-V-f and G/omega-V-f characteristics of Au/SiO2/n-Si capacitors

WOS: 000244808200011Au/SiO2/n-Si metal-insulator-semiconductor (MOS) structures with thermal growth oxide layer have been fabricated. The frequency dependence of capacitance-voltage (C-P) and conductance-voltage (G/omega-V) characteristics of these structures have been investigated taking into account the effect of the series resistance and interface states. The C-V and G/omega-V measurements have been carried out in the frequency range of 1 kHz-1 MHz at room temperature. The frequency dispersion in capacitance and conductance can be interpreted in terms of the interface states density (N-ss) and series resistance values (R-s). The interface states can follow the ac signal and yield an excess capacitance especially at low frequencies. The values of measured C and G/omega decrease in depletion region with increasing frequencies especially in low frequencies due to a continuous density distribution of interface states. The C-V plots exhibit anomalous peaks due to the N-ss and R-s effect. It has been experimentally found that the peak positions in the C-V plot shift towards positive voltages and the peak value of the capacitance decreases with increasing frequency. The effect of series resistance on the capacitance is found appreciable at high frequencies due to the interface state capacitance decreasing with increasing frequency. In addition, the high-frequency capacitance (C-m) and conductance (G(m)/omega) values measured under both reverse and forward bias were corrected for the effect of series resistance to obtain the real diode capacitance. Experimental results show that the locations of interface states between Si/SiO2 and series resistance have a significant effect on electrical characteristics of MOS structures. (c) 2006 Elsevier B.V. All rights reserved

The origin of anomalous peak and negative capacitance in the forward bias C-V characteristics of Au/n-GaAs contacts at low temperatures (T?300 K)

Au/n-GaAs contacts were fabricated using n-GaAs wafer with high doping concentration and their electrical characteristics were investigated via admittance measurements at low temperatures (T?300 K) at 1MHz. The main electronic parameters such as barrier height, depletion region width, doping concentration, series resistance and Fermi energy were obtained from experimental data. All these parameters showed dependence on temperature since different conduction mechanisms may play role at a certain voltage and temperature range. The forward bias capacitance-voltage curve exhibited an anomalous peak and then capacitance took negative values for each temperature. Such negative capacitance behaviour can be explained by the loss of interface charges located at junction, the existence of surface states, series resistance and a native interlayer. The decrease in series resistance and increase in surface states with increasing temperature were attributed to the decrease in band gap of GaAs and restructuring and reordering of surface charges. © 2020 National Institute of Optoelectronics. All rights reserved.Gazi Ãœniversitesi: GU-BAP.05/2019-26This work was supported by Gazi University Scientific Research Project (GU-BAP.05/2019-26).2-s2.0-8509052230