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Latreche A.,University of Bordj Bou Arreridj | Ouennoughi Z.,Laboratoire Optoelectronique et Composants
International Journal of Numerical Modelling: Electronic Networks, Devices and Fields | Year: 2015

In this study, we show clearly why unexpected observations have been reported in the current-voltage curves of Schottky diodes, containing barrier inhomogeneities generated by using the analytical results based on a Gaussian distribution model of barrier heights. The Chand's calculations have shown that the current (saturation current) at low temperatures may exceed the current (saturation current) at high temperatures when the effective barrier height is calculated from an appropriate integral with integration limits -∞ and +∞. In this new study, we show that the method followed by Chand to remove these anomalies is not accurate enough. We prove that the origin of these anomalies stems from the nature of a proper function f(φ) that moves to the negative barrier heights and takes large value of the integral at low temperatures than at high temperatures when it has large standard deviation (σ) and the discrepancies are not due to the integration limits as Chand concluded. In order to obtain results consistent with the thermionic emission-diffusion theory, the standard deviation must have lower values. Copyright © 2014 John Wiley & Sons, Ltd. Source

Latreche A.,University of Bordj Bou Arreridj | Ouennoughi Z.,Laboratoire Optoelectronique et Composants
Semiconductor Science and Technology | Year: 2013

We present a simple method for analysing the tunnelling current through Schottky barrier diodes on SiC, based on the modified Airy function (MAF) approach. The MAF method is accurate for linear-shaped barriers which is the case for the top of the Schottky barrier diodes. The results have been compared with those obtained by the conventional Wentzel-Kramers-Brillouin (WKB). This study proves that the WKB method is valid for the Schottky barrier diodes with and without the incorporation of Schottky barrier lowering under low or high bias voltage. © 2013 IOP Publishing Ltd. Source

Ouennoughi Z.,Laboratoire Optoelectronique et Composants | Toumi S.,FIIS | Weiss R.,Laboratoire Optoelectronique et Composants
Physica B: Condensed Matter | Year: 2014

In the present work we investigate the forward current-voltage (I-V) characteristics, over a wide temperature range 298-498 K, of Mo/4H-SiC Schottky diode for which aluminum ion implantation was used to create the high resistivity layer forming the guard ring. The (I-V) analysis based on Thermionic Emission (TE) theory shows a decrease of the barrier height φBand an increase of the ideality factor n when the temperature decreases. These anomalies are mainly due to the barrier height inhomogeneities at the metal/semiconductor interface as we get a Gaussian distribution of the barrier heights when we plot the apparent barrier height φapversus q/2kT. The mean barrier height and the standard deviation obtained values are φ¯B0=1.160 eV and σ0=88.049 mV, respectively. However, by means of the modified Richardson plot Ln(Is/T2)-(q2σ02/2k2T2) versus q/kT, the mean barrier height and the Richardson constant values obtained are φ¯B0=1.139 eV and A∗=129.425 A/cm2K2, respectively. The latter value of φ¯B0matches very well with the mean barrier height obtained from the plot of φapversus q/2kT. The Richardson constant is much closer to the theoretical value of 146 A/cm2K2. The series resistance Rsis also estimated from the forward current-voltage characteristics of Mo/4H-SiC Schottky contact. This parameter shows strong temperature dependence. The T0effect is validated for the 298-498 K temperature range for the used Schottky diode and provides a clear evidence for the barrier inhomogeneity at the Mo/4H-SiC interface. Finally, we note the impact of the implantation process as well as the choice of the used ion on the characterized parameters of the Schottky contact. © 2014 Elsevier B.V. Source

Messai Z.,Prisme Institute | Messai Z.,Laboratoire Optoelectronique et Composants | Messai Z.,University of Bordj Bou Arreridj | Ouennoughi Z.,Laboratoire Optoelectronique et Composants | And 6 more authors.
Applied Surface Science | Year: 2010

In this paper we study nanocrystalline zinc oxide thin films produced by oxidation of electrodeposited zinc nanolayers on a monocrystalline p-Si(1 1 1) substrate. The electrolyte used is ZnCl2, an aqueous solution of 4 × 10-2 mol/l concentration. Several deposits were made for various current densities, ranging from 13 mA/cm2 to 44 mA/cm 2, flowing through the solution at room temperature. A parametric study enabled us to assess the effect of the current density on nucleation potential and time as well as zinc films structure. The grazing incidence X-ray diffraction (GIXD) revealed that both Zn and ZnO films are polycrystalline and nanometric. After 1-h oxidation of zinc films at 450 °C in the open air, the structural analyses showed that the obtained ZnO films remained polycrystalline with an average crystal size of about 47 nm and with (1 0 0), (0 0 2) and (1 0 1) as preferential crystallographic orientations. © 2010 Elsevier B.V. Source

Latreche A.,Laboratoire Optoelectronique et Composants | Ouennoughi Z.,Laboratoire Optoelectronique et Composants | Sellai A.,Sultan Qaboos University | Weiss R.,FIIS | Ryssel H.,FIIS
Semiconductor Science and Technology | Year: 2011

The electrical characteristics of ion-implanted guard rings for molybdenum (Mo) Schottky diodes on 4H-SiC are analyzed on the basis of the standard thermionic emission model and the assumption of a Gaussian distribution of the barrier height. For edge termination, high-resistivity guard rings manufactured by carbon and aluminum ion-implanted areas were used. Extractions of barrier heights of molybdenum on silicon carbide (4H-SiC) Schottky diodes have been performed on structures with various gate metallization, using both current-voltage-temperature (I-V-T) and capacitance-voltage (C-V) measurements. Characteristic features of the Schottky barrier height (SBH) are considered in relation to the specific dose of the carbon- or aluminum-implanted guard ring. Contacts showed excellent Schottky behavior ideality factors between 1.02 and 1.24 in the range of 303-473 K. The measured SBHs were between 0.92 and 1.17 eV in the same temperature range from I-V-T characteristics. The variations in the barrier height, which is significantly temperature- and implantation-dose- dependent, are well fitted to a single Gaussian distribution function. Experimental results agree reasonably well by using this approach, particularly for carbon implantation dose of 1.75 × 1014 cm-2, and a mean barrier height () of 1.22 eV and zero bias standard deviation σ0 = 0.067 V have been obtained. Furthermore, the modified Richardson plot according to the Gaussian distribution model resulted in a mean barrier height () and a Richardson constant (A*) of 1.22 eV and 148 A cm-2 K-2, respectively. The A* value obtained from this plot is in very close agreement with the theoretical value of 146 A cm -2 K-2 for n-type 4H-SiC. Therefore, it has been concluded that the temperature dependence of the forward (I-V) characteristics of the Mo/4H-SiC contacts can be successfully explained on the basis of a thermionic emission conduction mechanism with Guassianly distributed barriers. © 2011 IOP Publishing Ltd. Source

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