Gate width dependence on backscattering characteristics in the nanoscale strained complementary metal-oxide-semiconductor field-effect transistor

Abstract

It is found that the ballistic efficiency, channel backscattering ratio, and injection velocity, which are the most important parameters for the ballistic transport, are greatly influenced by the stress characteristic in the channel even on the same gate length device. The narrower gate width device provides the best performance for the n-type field-effect transistor (n-FET) with the same gate length. Thus, the multichannel device is proposed to enhance the n-FET performance in the circuit design. The stress distribution with different device structures were simulated by the three-dimensional finite element mechanical stress simulation, and ballistic efficiency and injection velocity were calculated theoretically based on the stress characteristic. The theoretical calculation and the experimental data indicate the causes of the higher ballistic efficiency and injection velocity in narrower gate width devices to be the strain-induced modulation of the carrier mean-free path and smaller electron effective mass under the biaxial-like stress.