Table of Contents
Indian Journal of Materials Science
Volume 2013, Article ID 465905, 5 pages
http://dx.doi.org/10.1155/2013/465905
Research Article

60Co-Gamma Ray Induced Total Dose Effects on P-Channel MOSFETs

1Instrumentation Department, Uniphos Envirotronic Pvt. Ltd., Vapi 396195, India
2Department of Electrical Engineering, Indian Institute of Technology, Mandi 175001, India
3Department of Studies in Physics, Kuvempu University, Shankaraghatta 577451, India
4Department of Physics, Mangalore University, Mangalore 574199, India
5Department of Physics, Bengaluru University, Bengaluru 560056, India

Received 25 June 2013; Accepted 28 August 2013

Academic Editors: D. S. Patil and D. Sinha

Copyright © 2013 Shashank Nagaraj et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Total Dose Effect (TDE) on solid state devices is of serious concern as it changes the electrical properties leading to degradation of the devices and failure of the systems associated with them. Ionization caused due to TDE in commercial P-channel Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) has been studied, where the failure mechanism is found to be mainly a result of the changes in the oxide properties and the surface effects at the channel beneath the gate oxide. The threshold voltage of the MOSFETs was found to shift from −0.69 V to −2.41 V for a total gamma dose of 1 Mrad. The net negative threshold shifts in the irradiated devices reveal the major contribution of oxide trapped charges to device degradation. The radiation induced oxide and interface charge densities were estimated through subthreshold measurements, and the trap densities were found to increase by one order in magnitude after a total gamma dose of 1 Mrad. Other parameters like transconductance, subthreshold swing, and drain saturation current are also investigated as a function of gamma dose.