Different types of degradation and recovery mechanisms on NBT stress for thin SiO₂ films by On-the-Fly measurement

We demonstrate the Negative Bias Temperature Instability (NBTI) characteristics induced by the conventional high voltage and the hole injection stresses using an On-the-Fly measurement technique. In the case of the conventional stress, the recovery rate just after the stress (<30 μsec) is much larger than that of the hole injection stress in which stress gate bias voltage is same as the operation condition. Then the recovery rate of conventional stress becomes same as that of the high hole injection stress but it is still larger than that of the low hole injection stress. It is considered that the conventional stress causes the excess trap occupation and the different degradation from the operation condition. The low hole injection under the same gate voltage as the operation condition causes the same degradation and recovery mechanisms as operation condition. An accurate NBTI lifetime prediction based on the gate voltage acceleration stress is very difficult especially when using the On-the-Fly characterization method.