Effect of Channel Profile Engineering on Hot Carrier Reliability in nMOSFETs with 100 nm Channel Lengths

ABSTRACTHot-carrier effect was studied for different channel doping profiles in nMOSFET devices with effective channel length near 100 nm using a device simulator. The test structures for device simulation were generated using gate oxide thickness of 3 nm. The channel doping profiles used were abrupt- and graded-retrograde types with low surface and high substrate concentrations, and conventional step profiles with high surface and low substrate concentrations. For accurate device simulation, a hydrodynamic model for semiconductors was used to simulate the non-local transport phenomena in the devices. The simulation results indicate that for ultra-short channel devices, the current drivability and the hot-carrier effects depend on the shape of channel doping profiles. For a given supply voltage, the hot-carrier effects in ultra-short channel devices can be controlled by optimizing the channel doping profiles.