Distinguishing the effects of oxide trapped charges and interface states in DDD and LATID nMOSFETs using photon emission spectroscopy

Abstract

Photon emission spectra of double-diffused drain (DDD) and large-angle-tilt-implanted-drain (LATID) submicron n-channel MOSFETs after hot-carrier stressing under maximum substrate current lsub(max) and maximum gate current lg(max) conditions were investigated. The results showed that the difference spectra, obtained by subtracting the devices' pre-stress spectra from the post-stress spectra, could be used for distinguishing the effects of interface states and trapped charges. Interface states cause enhanced surface scattering and therefore increase the efficiency of photon emission while trapped charges drive the current away from the surface of the channel and reduce the photon emission efficiency.