Physica B 390 (2007) 179–184 Simulation studies of current transport in metal–insulator–semiconductor Schottky barrier diodes Subhash Chand , Saroj Bala Department of Applied Sciences, National Institute of Technology, Hamirpur 177 005 (HP), India Received 29 June 2006; received in revised form 8 August 2006; accepted 9 August 2006 Abstract The current–voltage characteristics of Schottky diodes with an interfacial insulator layer are analysed by numerical simulation. The current–voltage data of the metal–insulator–semiconductor Schottky diode are simulated using thermionic emission diffusion (TED) equation taking into account an interfacial layer parameter. The calculated current–voltage data are fitted into ideal TED equation to see the apparent effect of interfacial layer parameters on current transport. Results obtained from the simulation studies shows that with mere presence of an interfacial layer at the metal–semiconductor interface the Schottky contact behave as an ideal diode of apparently high barrier height (BH), but with same ideality factor and series resistance as considered for a pure Schottky contact without an interfacial layer. This apparent BH decreases linearly with decreasing temperature. The effects giving rise to high ideality factor in metal–insulator–semiconductor diode are analysed. Reasons for observed temperature dependence of ideality factor in experimentally fabricated metal–insulator–semiconductor diodes are analysed and possible mechanisms are discussed. r 2006 Elsevier B.V. All rights reserved. PACS: 73.30.+y; 73.40.Ns; 73.40.Qv Keywords: Schottky diodes; Metal–insulator–semiconductor Schottky diodes; Numerical simulation; Barrier height; Current–voltage characteristics; Interfacial layer 1. Introduction The metal–insulator–semiconductor (MIS) diode is the most useful device in the study of semiconductor surfaces. Since, the reliability and stability of all the semiconductor devices are intimately related to their surface conditions, an understanding of surface physics with the help of MIS diodes is of great importance to device operation [1–6]. The barrier height (BH) is an important parameter that determines the electrical characteristics of metal–semiconductor (MS) con- tacts. Schottky BH is defined as the difference in the energy between the metal Fermi level and band edge of the semiconductor majority carriers at the junction for a metal and semiconductor in contacts [1–3]. In general, being a Schottky contact configuration, its performance and relia- bility is drastically determined by the interface quality between the deposited metal and the semiconductor surface. It is well known that, unless specially fabricated, a Schottky barrier diode posses a thin interfacial native oxide layer between metal and semiconductor. The existence of such an insulating layer converts the MS device into a MIS device and has strong influence on its current–voltage (I–V) characteristics as well as the barrier parameters of Schottky diode [3,7–15]. There are several possible reasons of error that cause deviation of the ideal behaviour of Schottky diodes with and without an interfacial insulator layer. These include the particular distribution of interface states [2,16], the series resistance [9,15,17], applied bias voltage [9,10,15,17,18] and device temperature [1,2,8–10]. In this paper, we analyse effect of an interfacial layer on I–V characteristics of Schottky diode using simulation studies. Based on thermionic emission diffusion (TED) theory, the current through a Schottky diode as a function of ARTICLE IN PRESS www.elsevier.com/locate/physb 0921-4526/$ - see front matter r 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.physb.2006.08.011 Corresponding author. Tel.: +91 1972 254136; fax: +91 1972 254005. E-mail address: schand@nitham.ac.in (S. Chand).