Enhanced Saturation Current Sensitivities to Charge Trapping and Illumination in MOS Tunnel Diode by Inserting Metal in Gate Dielectric
Journal
Applied Physics A
Journal Volume
122
Journal Issue
6
Pages
5108-5120
Date Issued
2016
Author(s)
Abstract
The enlarged two-state phenomenon in the current–voltage (I–V) characteristic of metal–oxide–semiconductor (MOS) tunnel diode (TD) after negative/positive constant voltage stress (negative/positive CVS) was investigated. It was found that the reverse saturation tunnel current of MOS TD is proportional to the Schottky barrier height of holes, which is determined by the intensity of fringing field (FF) at device edge. With the aid of high permittivity dielectric and screening effect by embedded metal in the MOS structure, the FF was enhanced, which was confirmed by TCAD simulations. Because of the FF enhancement, after proper electrical treatments of voltage stressing, the intensified quantity of electron trapping/de-trapping was found at device edge, which augmented the modulation of Schottky barrier height of holes. As a result, much variation of reverse saturation tunnel current was exhibited, and hence, the enlarged two-state behavior was achieved. The endurance characteristics were also demonstrated to show that the trapped electrons are more stable in the MOS structure with embedded aluminum. Moreover, benefited from FF enhancement, the enlarged photosensitivity of the I–V characteristics of the sample with high permittivity dielectric and embedded aluminum was obtained. The mechanisms of the enlarged split of current behaviors after suitable CVS and illumination treatments are also discussed for these observations.
SDGs
Type
journal article