Effects of high electrical-field stressing on hall mobility and carrier concentration in MOSFET's

The effect of high field stress on inversion layer mobility and carrier concentration in MOSFET's was studied by the use of Hall effect measurements at 77 and 298 K. The results show that Coulomb scattering by the increased interface charges causes mobility degradation. The near-threshold results are also consistent with the carrier fluctuation model. The mobility degradation is the most severe at low bias and low temperature. In contrast to former speculations made by a few investigators, Hall measurement results showed no decrease of mobile carrier concentration at the same effective gate bias in the entire bias range investigated. The mobility degradation is found to be strongly dependent on the gate oxide thickness of samples subjected to the same stress charges.