Modelling of the influence of charges trapped in the oxide on theI(V_g) characteristics of metal–ultra-thin oxide–semiconductor structures

Abstract

This paper deals with the theoretical and experimental influences of the charge trapped in the oxide of metal/ultra-thin oxide/semiconductor structures. It focuses on the two characteristics current-voltage I (V g ) and voltage-charges injected V g (Q inj ) (V g is the voltage applied, Q inj is the injected charge) when the conduction is of the Fowler-Nordheim type. The charge is trapped in the thin oxide after injection of a constant current at high field (>12 MV cm −1 ) from the metal (in accumulation regime: V g < 0). This study considers that, after a given injection, the charge centroid is fixed during the acquisition of the I (V g ) characteristics.A method is proposed to determine the trapped charge characteristics (density and centroid) by analysing the theoretical and experimental I (V g ) and V g (Q inj ) characteristics. It is shown that the constant current injection creates a charge trapped in the oxide near the cathode. When the injected charge increases, the trapped charge density increases linearly and the charge centroid position shifts exponentially towards the injecting electrode. These results enable us to draw conclusions on the instability of the trapped charge. Indeed the increase in the charges injected causes the movement of the charge centroid towards the cathode.

A Theoretical Study on Electron Tunneling Current in Isotropic High-κ Dielectric Stack-Based MOS Capacitors with Charge Trapping

“…Several studies have been performed to discuss the transmittance and tunneling current in highκ dielectric stack-based MOSFETs by taking into account the effect of charge trapping in the longitudinal motion of electrons [4][5]. The coupling effect between transverse-longitudinal motion represented by an electron velocity in the gate and anisotropic masses have been considered in the calculation of transmittance and tunneling current in the MOS capacitor with charge trapping [6].…”