Study on the relation between interface trap creation and MOSFET degradation under channel hot carrier stressing at cryogenic temperatures

Abstract

In general, the degradation mechanism of MOSFETs has been discussed relating hydrogen. For instance, the interface traps are created due to the Si-H bond breakage at the MOS interface by hot carriers under electrical stressing. In addition, it is also reported that hydrogen also relates to the bulk trap creation. However, these hydrogen-related degradation mechanisms have been discussed based on the results within conventional measurement temperature region. However, the degradation mechanisms at cryogenic temperature have yet to be fully clarified. In this paper, the degradations of MOSFETs under a channel hot carrier stressing in the temperature range of 77 K ~ 300 K are investigated. Especially, we focus on the degradation of MOSFETs due to the interface trap creation. As a result, the MOSFETs degrade more under cryogenic temperature comparing to that near at the room temperature. This result implies the existing the additional degradation mechanism at cryogenic temperature.