Effective density-of-states distribution of polycrystalline silicon thin-film transistors under hot-carrier degradation

Abstract

In this work, quantitative information for nonuniform hot-carrier degradation, especially under mild stressing condition, is investigated. A test structure capable of revealing hot-carrier degradations of polycrystalline silicon (poly-Si) thin-film transistors in specific portions of the channel is employed. Effective density-of-states (DOS) distributions at the damaged sites can be extracted using field-effect conductance method, thus providing an effective tool to evaluate the impact of hot-carrier degradations. By measuring along individual sections of the channel, it becomes possible to extract the DOS for the device as a whole. The combination of the proposed test structure and DOS extraction technique also provides a powerful tool for modeling and simulating current-voltage characteristics of thin-film transistors under hot-carrier stressing.