We present the results of experiments studying the effect of carrier depletion and interfacial stress on time to breakdown of'thin oxide films during constant current stressing High energy electrons resulting from carrier depletion conditions increase damage to oxides during tunneling. Carrier depletion conditions cause a dramatic decrease in time to breakdown and increase the number of early failures substantially. Mechanical interfacial stress results in a degradation in oxide reliability. Anode interfacial stress has been uniquely isolated from other phenomena such as cathode surface roughness, and has been shown to result in accelerated breakdown. These results have implications on oxide reliability and on test methodologies to obtain a measure of the same