Effect of Series Resistance and Interface State Density on Electrical Characteristics of Au/SiO2/n-GaN Schottky Diodes

Author(s) M. Siva Pratap Reddy1, B. Prasanna Lakshmi1, A. Ashok Kumar2, V. Rajagopal Reddy1

1 Sri Venkateswara University, Tirupati – 517 502, Andhra Pradesh, India

2 Y.S.R Engineering College of Yogivemana University, Proddatur  516 630, Andhra Pradesh, India

Е-mail sivamtech2005@rediffmail.com
Issue Volume 3, Year 2011, Number 1, Part 4
Dates Received 04 February 2011, published online 17 October 2011
Citation M. Siva Pratap Reddy, B. Prasanna Lakshmi, A. Ashok Kumar, V. Rajagopal Reddy, J. Nano- Electron. Phys. 3 No1, 837 (2011)
PACS Number(s) 73.40.Qv; 85.30.Hi
Key words Metal-insulator-semiconductor contacts, Schottky barrier hieght, Ideality factor (9) , Interface densities.
We have investigated the current-voltage (I−V) characteristics of (Au/SiO2/n-GaN) metal-insulator-semiconductor (MIS) Schottky diodes and compared with (Au/n-GaN) metal-semiconductor (MS) Schottky diode. The effect of SiO2 on the surface preparation of n-GaN (MIS) Schottky diode is analyzed. The extracted Schottky barrier height and ideality factor of the MS Schottky diode is found to be 0.79 eV and 1.45 respectively. It is observed that the Schottky barrier height increases to 0.86 eV and ideality factor decreases to 1.3 for MIS diode. The interface state density as determined by Terman’s method is found to be 3.79 × 1012 and 3.41 × 1010 cm-2 eV-1 for the MS and MIS Schottky diodes, respectively. In addition, the values of series resistance (Rs) are determined using Cheung’s method. The I−V characteristics confirmed that the distribution of Nss, Rs and interfacial layer are important parameters that influence the electrical characteristics of MIS Schottky diodes.