Effect of negative air corona-stress at slightly reduced pressure (congruent-to 0.1 Torr) has been investigated on metal-chlorinated oxide-semiconductor capacitors for different values of the high tension voltage. Interface traps along with oxide charges were found to be generated as a result of corona-stress. Room temperature annealing of the traps with time was found to occur only when the devices were highly damaged (i.e., the number of interface traps as well as oxide charges generated just after corona-stress was high). Water related traps were also found to be involved in the room-temperature annealing of the traps. The results have been analyzed on the basis of the different models proposed by different authors for the unmetallized surfaces and a plausible explanation has been presented.