Hot-electron-induced MOSFET degradationModel, monitor, and improvement

Evidence suggests that MOSFET degradation is due to interface-states generation by electrons having 3. 7 eV and higher energies. This critical energy and the observed time dependence is explained with physical model involving the breaking of the ≡ Si s H bonds. The device lifetime τ is proportional to Iₒₔ₁^-2. 9I₃^1. 9 Vₓ^1. 5. If I sub is large because of small L or large V d, etc. , τ will be small. I sub (and possibly light emission) is thus a powerful predictor of τ. The proportionality constant has been found to vary by a factor of 100 for different technologies, offering hope for substantially better reliability through future improvements in dielectric /interface technologies. A simple physical model can relate the channel field E m to all the device parameters and bias voltages. Its use in interpreting and guiding hot-electron scaling are described. LDD structures can reduce E m and I sub and, when properly designed, reduce device degradation.