SURFACE-PLASMONS AND BREAKDOWN IN THIN SILICON DIOXIDE FILMS ON SILICON

The anode hole injection model is based on a surface plasmon model in which the positive charge is generated by hole injection from the anod e, where it is generated via a surface plasmon mechanism resulting fin ally in oxide breakdown. Attempts to detect the surface plasmons can r ely only on indirect observations, such as electron-energy loss, the r adiative decay of the surface plasmons, or d(2)I/dV(2) measurements. T hese measurements show that the emission of surface plasmons is both a strong energy-loss mechanism and an electron-hole pair generation mec hanism, particularly in poly-Si/SiO2 or poly-Si/vacuum interfaces. Cal culation of the surface plasmon excitation threshold energy is shown t o decrease with increasing temperature and is also confirmed by experi ments. Thus, the positive charge density increases and the charge to b reakdown decreases with increasing temperature. We have also measured and observed the surface plasmon excitation threshold energy at the po ly-Si/SiO2 interface from the electron energy loss spectrum for the fi rst time. The surface plasmon mechanism explains the oxide thickness a nd gate thickness dependence of the positive charge density and temper ature dependence of the charge to breakdown. The calculated electron t hreshold energy to generate a positive oxide charge by the surface pla smon mechanism is EC-Si+ 2.24 eV. Also, the origin of substrate hole c urrent can be explained by this proposed mechanism. Therefore, the ano de hole injection model based upon surface plasmons is a reasonable th in oxide breakdown model that explains measured observations. (C) 1998 American Institute of Physics.