Characterization of interface defects in BiFeO<inf>3</inf> metal–oxide–semiconductor capacitors deposited by radio frequency magnetron sputtering

In this work, we study the structural and electrical properties of BiFeO3 MOS capacitors with a special focus on the oxide–semiconductor interface for gate dielectric applications. For this purpose BiFeO3 thin films with a thickness of 300 nm were deposited on p-type Si (100) substrates at 0 °C by RF sputtering. Half of the films were annealed at 550 °C for 30 min in atmospheric environment while the other half were kept as-deposited. XRD and SEM measurements were performed for both samples for structural characterization. MOS capacitors were fabricated by evaporation technique using Al from samples. For electrical characterizations of MOS capacitors, capacitance–voltage (C–V), conductance–frequency (Gp/ω–F) and leakage current density–voltage (J–V) measurements were performed. The XRD analyses show that BiFeO3 thin films are polycrystalline with some impurity phases, which influence the electronic device properties. The formation of crystallization is confirmed by SEM measurements. Debye length, barrier height and flat band voltages showed variations due to the frequency dependent charges, partially originating from interface defects, in the device structure. Therefore ignoring effects of frequency dependent charges can lead to significant errors in the analysis of electrical characteristics of MOS capacitors. Moreover, the obtained results from analyses of C–V, Gp/ω–F and J–V characteristics of annealed samples depict that all measured and calculated parameters are of the same order for novel MOS devices. Hence, the BiFeO3 dielectric layer in fabricated MOS devices exhibits a stable insulation property for gate dielectric applications

Characterization of interface defects in BiFeO<inf>3</inf> metal–oxide–semiconductor capacitors deposited by radio frequency magnetron sputtering

© 2015, Springer Science+Business Media New York. In this work, we study the structural and electrical properties of BiFeO 3 MOS capacitors with a special focus on the oxide–semiconductor interface for gate dielectric applications. For this purpose BiFeO 3 thin films with a thickness of 300 nm were deposited on p-type Si (100) substrates at 0 °C by RF sputtering. Half of the films were annealed at 550 °C for 30 min in atmospheric environment while the other half were kept as-deposited. XRD and SEM measurements were performed for both samples for structural characterization. MOS capacitors were fabricated by evaporation technique using Al from samples. For electrical characterizations of MOS capacitors, capacitance–voltage (C–V), conductance–frequency (G p /ω–F) and leakage current density–voltage (J–V) measurements were performed. The XRD analyses show that BiFeO 3 thin films are polycrystalline with some impurity phases, which influence the electronic device properties. The formation of crystallization is confirmed by SEM measurements. Debye length, barrier height and flat band voltages showed variations due to the frequency dependent charges, partially originating from interface defects, in the device structure. Therefore ignoring effects of frequency dependent charges can lead to significant errors in the analysis of electrical characteristics of MOS capacitors. Moreover, the obtained results from analyses of C–V, G p /ω–F and J–V characteristics of annealed samples depict that all measured and calculated parameters are of the same order for novel MOS devices. Hence, the BiFeO 3 dielectric layer in fabricated MOS devices exhibits a stable insulation property for gate dielectric applications

Frequency dependent electrical characteristics of BiFeO<inf>3</inf> MOS capacitors

The frequency dependent electrical behavior of BiFeO3 MOS capacitors was studied in this work. BiFeO3 thin films were deposited on p-type Si (1 0 0) substrates at 0 C by RF magnetron sputtering and the structures were investigated by XRD and SEM measurements. Electrical characteristics of the capacitors were determined by C-V and G/ω-V measurements for several frequencies from 10 kHz to 1 MHz. The results illustrate that the C-V and G/ω-V characteristics of the devices are sensitive to both frequency and voltage variations. C-V characteristic variations decrease with increasing frequency and are mainly resulting from the presence of interface states (Ns) between silicon and BiFeO 3. The G/ω-V characteristics of devices were found to be different for low and high frequencies. Variations in G/ω-V characteristics in the low frequency regions (f < 500 kHz) decrease with increasing frequency, however, in high frequency regions they increase with increasing frequency. For high frequency (1 MHz) characteristics of the capacitor, the capacitance has been corrected by eliminating the effects of the series resistance (Rs) because of its negligible response to high frequency; however, for conductance measurements it cannot be ignored. The C-V and G/ω-V analysis demonstrate that Rs and Ns are important factors that can affect electrical characteristics of the capacitor. © 2013 Elsevier B.V. All rights reserved

Investigation of parameters of new MAPD-3NM silicon photomultipliers

In the presented work, the parameters of a new MAPD-3NM-II photodiode with buried pixel structure manufactured in cooperation with Zecotek Company are investigated. The photon detection efficiency, gain, capacitance and gamma-ray detection performance of photodiodes are studied. The SPECTRIGMAPD is used to measure the parameters of theMAPD-3NM-II and scintillation detector based on it. The obtained results show that the newly developedMAPD-3NM-II photodiode outperforms its counterparts in most parameters and it can be successfully applied in space application, medicine, high-energy physics and security