Comparison of characteristics of n-channel and p-channel MOSFET´s for VLSI´s

A comparison of device characteristics of n-channel and p-channel MOSFET\´s is made from the overall viewpoint of VLSI construction. Hot-carrier-related device degradation of device reliability, as well as effective mobility, is elaborately measured for devices having effective channel lengths of 0.5-5 µm. From these experiments, it is found that hot-electron injection due to impact ionization at the drain, rather than "lucky hot holes," imposes a new constraint on submicrometer p-channel device design, though p-channel devices have been reported to have much less trouble with hot-carrier effects than n-channel devices do. Additionally, p-channel devices are found to surpass n-channel devices in device reliability in that they have a highest applicable voltage BVDCthat is more than two times as high as for n-channel devices. It is also experimentally confirmed that the effective hole mobility approaches the effective electron mobility when effective channel length µm. These significant characteristics of p-channel devices imply that p-channel devices have important advantages over n-channel devices for realization of sophisitcated VLSI\´s with submicrometer dimensions. It is also shown that hot holes, which may create surface states or trap centers, play an important role in such hot-carrier-induced device degradation as transconductance degradation.