High field related thin oxide wearout and breakdown

The high voltage wearout and breakdown of thin silicon oxides has been described in terms of traps generated inside of the oxide and at the interfaces by a high field emission process. The trap generation was accompanied by the motion of atoms which resulted in permanent traps fixed in space. Breakdown occurred when the local density of traps exceeded a critical density. The charge state of these traps could easily be changed by application of low voltages after the high voltage stresses. The energy levels of the traps varied depending on the probability of trap generation. This model has been applied to analyze the thickness, field, polarity, time, and temperature dependences of oxide wearout and breakdown observed in oxides thinner than 22 mn. It was concluded that the wearout process in oxides thinner than 22 nm was determined by the electric fields applied to the oxides and not by the passage of currents through the oxides.>