Hot-electron design constraints for one-micron IGFET's

An approach is described for determining the hot-electron-limited voltages for silicon IGFET's of small dimensions. The approach was followed in determining the room-temperature and the 77°K hot-electron-limited voltages for a device designed to have a minimum channel length of one micron. The substrate-hot-electron limits were determined from a verified empirical model. The channel-hot-electron limits were determined empirically from measurements of the injection current as a function of voltage and from long-term stress experiments. For the one-micron design considered, the channel-hot-electron limits are lower than the substrate-hot-electron limits. The maximum voltage, VGS=VDS, is 4.75 V at room temperature (25°C) and 3.5 V at 77°K. More details of the voltage limits as well as the approach for determining them are discussed. An example of a circuit designed to operate within these hot-electron voltage limits is also discussed.