Variability and reliability in ultra-scaled MOS devices: Evaluation at the nanoscale and impact on device and circuit functionality

In this work, the approaches adopted at (Universitat Autònoma de Barcelona) UAB to evaluate the nanoscale sources of device variability related to the MOSFETs gate oxide and to analyse the impact of device variability and aging on circuit performance and reliability are described. First, a Conductive Atomic Force Microscope is used to evaluate the effects of processing on the morphological and electrical characteristics of gate dielectrics at the nanoscale. As example, the dependence of the electrical properties of Al2O3/SiO2 stacks on a thermal annealing at different temperatures is analyzed. Second, a reliability circuit simulation methodology to transfer the variability and aging effects in devices up to circuit level, which combines Montecarlo and SPICE simulations, is presented. The methodology is applied to evaluate the impact of threshold voltage time-dependent variability in differential amplifiers performance and reliability. © 2011 Nova Science Publishers, Inc. All rights reserved.