Frequency dependence of forward capacitance-voltage characteristics of Schottky barrier diodes
TL;DR: In this paper, the frequency dependence of forward capacitance-voltage characteristics of Schottky barrier diodes were investigated by considering the series resistance effect, and the peak value of the capacitance was found to vary with series resistance, interface state density and the frequency of the a.c. signal.
Abstract: The frequency dependence of forward capacitance-voltage characteristics of Schottky barrier diodes were investigated by considering the series resistance effect. It is seen that in presence of a series resistance, the capacitance-voltage plot exhibits a peak. The peak value of the capacitance is found to vary with series resistance, interface state density and the frequency of the a.c. signal. The effect of series resistance on the capacitance is found appreciable at higher frequencies when capacitance decreases rapidly with frequency. On the other hand, the conductance of the diode increases with frequency in the high frequency limit. Such a variation in conductance limits the use of well known conductance technique to determine interface state density.
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TL;DR: In this article, the effect of surface preparation on the energy density distribution and relaxation time of the interface state of Au/InSb/InP(1.0) Schottky-type diodes was investigated.
Abstract: The purpose of this paper is to characterize interface states in Au/InSb/InP(1 0 0) Schottky-type diodes and determine the effect of InSb surface preparation on the energy density distribution and relaxation time of the interface state. In the latter diode, InSb forms a fine restructuration layer allowing to block In atoms migration to surface. We have proceeded as follows: first, a great amount of antimony has been evaporated and, as a second step, the excess antimony is removed by heating the substrate at 300°C. The characteristic parameters of the interface states are derived from the capacitance-voltage C ( V G ), conductance–voltage G ( V G ) measured as a function of frequency and current–voltage I ( V G ) under forward biases. The mean density of interface states N ss estimated was 3.05×10 12 eV −1 cm −2 , the interface states were responsible for the non-ideal behavior of the I ( V G ) characteristics of the diodes. The relaxation times are independent of the bias and varies with N ss in the range 7.1×10 −4 s and 3.7×10 −3 s.
124 citations
TL;DR: In this article, the effect of series resistance on capacitance and frequency characteristics of Zn/p-Si Schottky diodes with high resistivity has been given by admittance spectroscopy.
Abstract: Analysis of Zn/p–Si Schottky diodes (SDs) with high resistivity has been given by admittance spectroscopy. The importance of the series resistance in the determination of energy distribution of interface states and especially their relaxation time in the SDs with high resistivity has been considered. The effect of the series resistance on capacitance–conductance/frequency characteristics has been given by comparing experimental data with theoretical data. The interface state density Nss from the admittance spectroscopy ranges from 1.0×1012 cm−2 eV−1 in 0.720-Ev eV to 2.03×1012 cm−2 eV−1 in 0.420-Ev eV. Furthermore, the relaxation time ranges from 4.20×10−5 s in (0.420-Ev) eV to 3.20×10−4 s in (0.720-Ev) eV. It has been seen that the interface state density has a very small distribution range (1.0–2.03×1012 cm−2 eV−1) that is ascribed to the predominant termination with hydrogen of the silicon surface after HF treatment.
122 citations
TL;DR: In this paper, a hybrid device consisting of a graphene/silicon (Gr/Si) Schottky diode in parallel with a Gr/SiO2/Si capacitor was proposed for high-performance photodetection.
Abstract: We propose a hybrid device consisting of a graphene/silicon (Gr/Si) Schottky diode in parallel with a Gr/SiO2/Si capacitor for high-performance photodetection. The device, fabricated by transfer of commercial graphene on low-doped n-type Si substrate, achieves a photoresponse as high as 3 AW^(-1) and a normalized detectivity higher than 3.5 10^12 cmHz^(1/2) W^(-1) in the visible range. The device exhibits a photocurrent exceeding the forward current, because photo-generated minority carriers, accumulated at Si/SiO2 interface of the Gr/SiO2/Si capacitor, diffuse to the Gr/Si junction. We show that the same mechanism, when due to thermally generated carriers, although usually neglected or disregarded, causes the increased leakage often measured in Gr/Si heterojunctions. At room temperature, we measure a zero-bias Schottky barrier height of 0.52 eV, as well as an effective Richardson constant A**=4 10^(-5) Acm^(-2) K^(-2) and an ideality factor n=3.6, explained by a thin (< 1nm) oxide layer at the Gr/Si interface.
108 citations
19 Apr 2017
TL;DR: In this article, a hybrid device consisting of a graphene/silicon (Gr/Si) Schottky diode in parallel with a Gr/SiO2/Si capacitor was proposed for high-performance photodetection.
Abstract: We propose a hybrid device consisting of a graphene/silicon (Gr/Si) Schottky diode in parallel with a Gr/SiO2/Si capacitor for high-performance photodetection. The device, fabricated by transfer of commercial graphene on low-doped n-type Si substrate, achieves a photoresponse as high as and a normalized detectivity higher than in the visible range. It exhibits a photocurrent exceeding the forward current because photo-generated minority carriers, accumulated at Si/SiO2 interface of the Gr/SiO2/Si capacitor, diffuse to the Gr/Si junction. We show that the same mechanism, when due to thermally generated carriers, although usually neglected or disregarded, causes the increased leakage often measured in Gr/Si heterojunctions. We perform extensive I–V and C-V characterization at different temperatures and we measure a zero-bias Schottky barrier height of 0.52 eV at room temperature, as well as an effective Richardson constant A ** = and an ideality factor , explained by a thin (<1 nm) oxide layer at the Gr/Si interface.
104 citations
TL;DR: In this article, the energy distribution of the interface states in the inorganic semiconductor bandgap and their relaxation time in the energy range (0.41−Ev) to 0.65−Ev −eV have been determined from the low-capacitance-frequency (C-f) characteristics.
Abstract: The nonpolymeric organic compound pyronine-B film on a p-type Si substrate has been formed by means of the process of adding a solution of pyronine-B in methanol and evaporating the solvent. It has been seen that the pyronine-B/p-Si contact shows the rectifying behaviour and the reverse curves exhibit the excellent saturation. The barrier height and ideality factor values of 0.65 eV and 1.51, respectively, for this structure have been obtained from the forward bias current–voltage (I–V) characteristics. The energy distribution of the interface states in the inorganic semiconductor bandgap and their relaxation time in the energy range (0.41−Ev) to (0.65−Ev) eV have been determined from the low-capacitance–frequency (C–f) characteristics. The measurement frequency ranges from 50 Hz to 2 MHz. The low and intermediate frequency regions approximately range 50–700 Hz and 700 Hz–500 kHz, respectively. It has been seen that the interface state density has an exponential rise with bias from the midgap towards the top of the valence band. The relaxation time shows a slow exponential rise from the top of the valence band towards the midgap with the applied voltage.
100 citations
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TL;DR: In this article, a realistic characterization of the Si-SiO 2 interface is developed, where a continuum of states is found across the band gap of the silicon, and the dominant contribution in the samples measured arises from a random distribution of surface charge.
Abstract: Measurements of the equivalent parallel conductance of metal-insulator-semiconductor (MIS) capacitors are shown to give more detailed and accurate information about interface states than capacitance measurements. Experimental techniques and methods of analysis are described. From the results of the conductance technique, a realistic characterization of the Si–SiO 2 interface is developed. Salient features are: A continuum of states is found across the band gap of the silicon. Capture cross sections for holes and electrons are independent of energy over large portions of the band gap. The surface potential is subject to statistical fluctuations arising from various sources. The dominant contribution in the samples measured arises from a random distribution of surface charge. The fluctuating surface potential causes a dispersion of interface state time constants in the depletion region. In the weak inversion region the dispersion is eliminated by interaction between interface states and the minority carrier band. A single time constant results. From the experimentally established facts, equivalent circuits accurately describing the measurements are constructed.
1,658 citations
TL;DR: In this paper, the dependence of the barrier height of metal-semiconductor systems upon the metal work function is derived based on the following assumptions: (1) the contact between the metal and the semiconductor has an interfacial layer of the order of atomic dimensions; it is further assumed that this layer is transparent to electrons with energy greater than the potential barrier but can withstand potential across it.
Abstract: The dependence of the barrier height of metal-semiconductor systems upon the metal work function is derived based on the following assumptions: (1) the contact between the metal and the semiconductor has an interfacial layer of the order of atomic dimensions; it is further assumed that this layer is transparent to electrons with energy greater than the potential barrier but can withstand potential across it. (2) The surface state density (per unit area per electron volt) at the interface is a property only of the semiconductor surface and is independent of the metal. The barrier height φВn is defined here as the energy needed by an electron at the Fermi level in the metal to enter the conduction band of the semiconductor.
1,198 citations
TL;DR: Measured capacitance in excess of the space-charge capacitance is shown to be caused by the injection of minority carriers into the bulk semiconductor, rather than by the presence of interface states, as previously thought.
Abstract: We identify the physical origin of the excess capacitance at Schottky diodes without an interfacial layer, i.e., intimate Schottky contacts. Measured capacitance in excess of the space-charge capacitance is shown to be caused by the injection of minority carriers into the bulk semiconductor, rather than by the presence of interface states, as previously thought. Minority-carrier injection depends sensitively on the properties of the Ohmic back-contact.
199 citations
TL;DR: In this paper, the current transport mechanism in an MIS-tunnel diode has been studied by considering both the process of tunneling and the effect of pinholes in the insulating layer.
Abstract: The current transport mechanism in an MIS-tunnel diode has been studied by considering both the process of tunneling and the effect of pinholes in the insulating layer. It has been shown that in order to explain the experimental J - V characteristics of MIS-diodes, presence of a thin interfacial layer of thickness δ p within the pinholes should be considered. From an analysis of the tJ - V and C - V characteristics, a method has been suggested for the estimation of the value of δ p . The values of interface trap density and barrier height for the MOS-part of the diodes are also calculated. The dependence of barrier height on oxide thickness for the diodes is found to obey the barrier height model of Cowley and Sze.
187 citations
121 citations