A test structure for spectrum analysis of hot-carrier-induced photoemission from MOSFETs

Hot-carrier-induced photoemission of subquarter-micron n-MOSFETs is analyzed using a specially designed test structure, which has a wide channel width of 2.0 mm for sufficient photoemission intensity. Since the test structure consists of parallelconnected unit MOSFETs and photoemission images are uniform, it can be estimated that the measured spectra are the same as those from unit MOSFETs. The relation between photon counts and photon energy suggests that photon energy has a Boltzmann distribution, exp(-h(nu)/kT/sub e/). The electron temperature T/sub e/ calculated from the photon emission spectrum takes a minimum value at the channel length of 0.23 (mu)m. If T/sub e/ is related to device reliability, it suggests the possibility that the device structure optimized for a certain channel length may not be optimum for other channel length devices.