Width dependence of substrate and gate currents in MOSFET's

Width dependence of hot-electron currents in MOSFET's fabricated with LOCOS, non-LOCOS, and a modified LOCOS processes are studied. The experimental results show that the substrate and gate currents are apparently enhanced in narrow width devices. The enhancement, however, is due to different voltage drops across the source-drain series resistance. The voltage drops are usually larger in wider devices. After correcting for the resistance effect, the substrate and gate currents scale with the device width. With this typical LOCOS process, the bird's beak and in-diffusion of field implant dopants do not cause excess hot-electron activities along the channel/field edges as has been suspected. Some other LOCOS process could, of course, produce a different result. Studies using wide test devices must consider the series resistance effect. With this precaution taken, models derived from wide-channel data will be applicable to narrow-channel devices, at least for some processes.