Accelerated Dielectric Breakdown of Silicon Dioxide Films

Abstract

The time dependent, dielectric breakdown of thermally grown structures was studied as a function of oxide thickness and growth conditions, stressing temperature and electric field, and electrode material. With no field applied, thermal annealing of capacitors markedly increased the measurable defect density. In the range 200°–350°C, the time required to form 20 defects/cm2 is proportional to thickness and . The degradation without bias was much less, comparatively, when Mo, Pt, and polycrystalline‐Si electrodes were used, as well as when a phosphosilicate glass film was formed on the surface. Under electrothermal stressing, the breakdown time decreased almost exponentially with applied field and, in films over 200Aå thick, was thermally activated with an energy 1.4 ± 0.2 eV. The oxide thickness dependence of the wear‐out under bias varied according to the applied field and ranged from the 2.1 power of the thickness at 2 MV/cm to the 5.5 power at 7 MV/cm. A model is described according to which the generation of the interface states, leading to a decrease of the injecting barrier height and attendant large increases in current, is probably responsible for the subsequent dielectric breakdown.