The hot carrier effect of NMOSFETs and PMOSFETs has been investigated for different inter-metal-oxide (IMO) deposition conditions. It was found that the hot carrier effect lifetime of NMOSFETs using silane-based oxide deposition can be more than two orders of magnitude longer than that of NMOSFETs using tetraethylorthosilicate (TEOS) based deposition, while PMOSFETs exhibit more net electron trapping. TEOS IMO apparently increases the rate of hole trapping and hole-induced generation of bulk and interface traps. A Si-rich oxide deposition condition improves the hot carrier lifetime, but does not overcome the deleterious effect of an additional TEOS oxide layer. IMO only influences the charge trapping properties of gate oxide interface in the vicinity of the source-drain gate edges and therefore affects short channel devices more strongly.