Defect generation in field-effect transistors under channel-hot-electron stress

Abstract

Nonuniform point-defect generation in n-channel metal-oxide-semiconductor field-effecttransistors under channel-hot-electron stress conditions is shown to have a similar origin as defects created with uniform stress conditions using Fowler-Nordheim tunneling, direct tunneling, or substrate-hot-electron injection. For all stressing modes, defect generation is related to the electron energy delivered to the appropriate silicon region near its interface with the thin-gate-oxide layer. A few of these hot electrons release a mobile species (believed to be hydrogen related) which can move hundreds of nm away from any positively biased contacts creating defects along its path in both silicon and oxide layers of the device. Channel-hot-electron degradation due to defect buildup along the channel is studied here as a function of stressing conditions, channel length, gate oxide thickness, and oxide processing. Procedures for predicting circuit failure under any operating conditions for logic and memory chips due to the total buildup of these defects are discussed. © 2000 American Institute of Physics.