Effect of Ambient on the Recovery of Hot-Carrier Degraded Devices

Abstract

nMOSFETs have been degraded by hot-carrier injection and recovered by annealing in various ambients. Hydrogen will depassivate from the interface due to the hot-carriers, creating dangling bonds, which will cause a shift in the various parameters like the threshold voltage, the subthreshold swing and the interface defect density. This paper investigates how the various ambients (argon, hydrogen, hydrogen plasma and atomic hydrogen) influence the recovery rate of these parameters. Results are discussed in the framework of Stesmans' model for hydrogen passivation at the interface. Furthermore, the influence of a silicon nitride scratch protection layer on the recovery is investigated. These results can be used to enhance the recovery rate and achieve more recovery at a lower anneal temperature, which is important for delaying the accumulative effect of hotcarrier degradation and, as such, extending the device lifetime.

Compact Physics Hot-Carrier Degradation Model Valid over a Wide Bias Range

“…Such a procedure required a measurement time of ∼0.75 s, and therefore HCD was assessed with the corresponding delay. Although recovery of HCD (or more precisely, passivation of P b centers that were created by the rupture of Si-H bonds [56][57][58][59]) was reported by several groups [60][61][62][63][64], this process was shown to have a significant rate only at temperatures of 150 • C or higher. As our experiments were conducted at room temperature, we can conclude that ∆I d,lin values did not recover during the aforementioned measurement delay.…”

Recovery of hot-carrier degraded nMOSFETs

“…At lower temperatures, a longer time is needed to get almost complete recovery (t a > decades for typical microchip operating temperatures). This section presents the results of recovery experiments on HCI degraded nMOSFETs by annealing in various ambients at a lower temperature and discusses how the recovery time can be decreased [214].…”