Has anyone tested high voltages >5V in silicon? Spice models only go to 5V, but the manual gives absolute gate-to-channel limits of 7.3V@25C for NMOS and 8.1V@25C for PMOS (presumably thick oxide devices). I would like to drive HV PMOS at 7V and NMOS at 6V for flash circuits

We weren't able to run that many tests, but our group saw Hot-Carrier injection at around 4+ volts on HV pFETs and tunneling at 8+ volts with a HV varactor. Our switching networks weren't accessible so I'm not sure if more complex circuits function at these voltages.