Surface plasmons and breakdown in thin silicon dioxide films on silicon

Abstract

The anode hole injection model is based on a surface plasmon model in which the positive charge is generated by hole injection from the anode, where it is generated via a surface plasmon mechanism resulting finally in oxide breakdown. Attempts to detect the surface plasmons can rely only on indirect observations, such as electron-energy loss, the radiative decay of the surface plasmons, or d2I/dV2 measurements. These measurements show that the emission of surface plasmons is both a strong energy-loss mechanism and an electron-hole pair generation mechanism, particularly in poly-Si/SiO2 or poly-Si/vacuum interfaces. Calculation of the surface plasmon excitation threshold energy is shown to decrease with increasing temperature and is also confirmed by experiments. Thus, the positive charge density increases and the charge to breakdown decreases with increasing temperature. We have also measured and observed the surface plasmon excitation threshold energy at the poly-Si/SiO2 interface from the electron energy loss spectrum for the first time. The surface plasmon mechanism explains the oxide thickness and gate thickness dependence of the positive charge density and temperature dependence of the charge to breakdown. The calculated electron threshold energy to generate a positive oxide charge by the surface plasmon mechanism is EC–Si+2.24 eV. Also, the origin of substrate hole current can be explained by this proposed mechanism. Therefore, the anode hole injection model based upon surface plasmons is a reasonable thin oxide breakdown model that explains measured observations.