The theoretical and experimental study on double-Gaussian distribution in inhomogeneous barrier-height Schottky contacts Nezir Yıldırım a , Abdulmecit Turut b, * , Veyis Turut c a Department of Physics, Faculty of Sciences and Arts, Bingöl University, Bingöl, Turkey b Atatürk University, Faculty of Sciences, Department of Physics, 25240 Erzurum, Turkey c Batman University, Faculty of Sciences and Arts, Department of Mathematics, Batman, Turkey article info Article history: Received 30 October 2009 Received in revised form 4 January 2010 Accepted 8 February 2010 Available online 15 February 2010 Keywords: Double-Gaussian distribution Schottky barrier diode Barrier inhomogeneity abstract We have considered multi-Gaussian distribution of barrier-heights for non-interactive barrier inhomoge- neities in the inhomogeneous Schottky diodes, and we have shown the presence of the intersecting behavior in the forward-bias current–voltage (I–V) curves for the double-Gaussian distribution model at low temperatures. We have tried to eliminate this effect by generating I–V curves at lower tempera- tures with the bias-dependent barrier-height expression which leads to the ideality factors greater than unity. For this calculation, we have obtained the expressions for the barrier-height change and ideality factor, and for bias-dependency of the BH for the multi-Gaussian model by following the literature. We have shown that the experimental forward-bias I–V curves coincide with the theoretical ones using the bias-dependent inhomogeneous BH expression at low and high temperatures in the double-Gaussian distribution of BHs. Ó 2010 Elsevier B.V. All rights reserved. 1. Introduction The fact that the fundamental physical mechanisms which determine Schottky barrier diode (SBD) parameters such as ideality factor n and barrier-height (BH) are fully understood has vital importance in all electronic and optoelectronics devices [1–7]. The analysis of the temperature dependence of the current–voltage (I–V) characteristics of the SBDs allows us to understand different aspects of conduction mechanisms because the I–V characteristics at room temperature only does not give detailed information about their conduction process [1–13]. However, a complete description of the charge carrier transport through a metal semiconductor (MS) contact is still a challenging problem [1–13]. As well-known, the temperature dependence of the BH and the ideality factor is generally observed in SBDs also if the pure thermionic emission is the most probable way of carrier transport. Sometimes, the tem- perature-dependent behavior of SBDs can only obey the special barrier inhomogeneity present in Schottky contacts which is re- cently described mainly with a Gaussian distribution function [8–14]. The BH in Schottky contacts is likely a function of the inter- face atomic structure and the atomic inhomogeneities at the MS interface [8–15]. Some of the authors [15–19] discussed the intersection behav- ior of the I–V characteristics of inhomogeneous Schottky contacts. Chand [16,17] has described an interesting effect that the calcula- tions have shown that the current at lower temperature may ex- ceed the current at higher temperatures which should appear in inhomogeneous Schottky contacts. He [16,17] used the apparent BH expression given by Song et al. [8] and Werner and Güttler [9] to simulate the forward-bias I–V curves of the non-interaction inhomogeneous SBDs. According to Chand [16,17], the intersection of ln(I)–V curves may occur because of decreasing apparent BH with decreasing temperature, which has been also supported by Osvald [18]. The same effect has also been confirmed by Yıldırım and Türüt [19]. Chand [16,17] has eliminated this affect with an ideality factor greater than unity for lower temperatures modifying the model of conventional Gaussian distribution of BHs. Yıldırım and Türüt [19] have supplied the fact that the experimental for- ward-bias I–V curves coincide with the theoretical ones using the bias-dependent BH expression at low and high temperatures. In the present study, we have shown the presence of the inter- secting behavior in the forward-bias I–V curves for the double- Gaussian distribution, considering multi-Gaussian distribution of BHs of the inhomogeneous SBDs suggested by Jiang et al. [20,21]. Then, we have obtained the expressions of the BH change and ide- ality factor and bias-dependency of the BH by following Werner and Güttler [9] and Refs. [19–22] for the multi-Gaussian model. The main effort in the manuscript is devoted to the deriving of the apparent barrier-height of inhomogeneous Schottky diode and its temperature dependence. We have supplied the fact that the exper- imental forward-bias I–V curves coincide with the theoretical ones 0167-9317/$ - see front matter Ó 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.mee.2010.02.007 * Corresponding author. Tel.: +90 442 2314171; fax: +90 442 2360948. E-mail address: aturut@atauni.edu.tr (A. Turut). Microelectronic Engineering 87 (2010) 2225–2229 Contents lists available at ScienceDirect Microelectronic Engineering journal homepage: www.elsevier.com/locate/mee