Introduction

Abstract

The present work deals with the study of the mobile ions in the silicon dioxide insulator, which has great importance because their presences affect significantly on the MOS structure characteristic. The subject is introduced with the necessary background concept of MOS structure dealing with various aspects of the oxides and their charges. A review is then presented of ionic transport mechanism and the measuring techniques of mobile ions concentration in the oxides. This is followed by theoretical approaches to determine the density of mobile ions as well as their density-distribution along the oxide thickness. In fact, three attempts have been discussed each makes use of different approaches. In the first attempt, the density of the mobile ions has been determined from experimental measurements through the use of different techniques such as the Charge Pumping (CP) technique associated with the Bias Thermal Stress (BTS) method. In the second attempt, the theoretical approaches for the mobile ions density-distribution have been described. In the last attempt, the theoretical model of the mobile ions density-distribution which is based on physical concepts at equilibrium state and ionic current–voltage characteristic of MOS structure have been presented.