The effects of device dimensions on the post-breakdown characteristics of ultrathin gate oxides

The effects of transistor channel length and width on post breakdown (BD) characteristics have been carefully investigated. As channel-length decreases, we have found that the probability of hard breakdown (HBD) increases and the soft breakdown (SBD) stability time decreases. However, these two quantities are found to be relatively insensitive to the channel width for long channel-length devices. Since SBD is unstable and finally causes the device failure, the so-called HBD prevalence ratio methodology has limitations which are particularly important in short-channel length devices. Our findings indicate that dimensional effects should be properly taken into account in the consideration of circuit reliability and for the application of any post-BD methodology.