The influence of mechanical strain on the nanoscale electrical characteristics of thin silicon dioxide film

Strain has been introduced into the channel region of metal-oxide-semiconductor (MOS) field-effect transistor to improve its operating speed in modern integrated circuits (IC). In this work, we investigated the influence of uniaxial compressive and tensile strains on the nanoscale electrical characteristics of thin gate silicon dioxide (SiO₂) films. Both the nanoscale I-V characteristics and cumulative failure distribution of oxide breakdown voltage at various positions on the surface of thin SiO₂ films were determined by using the conductive atomic force microscopy (CAFM). It is found that, for either compressive or tensile uniaxial strain, the region in which the highest strain (the central region) exists always exhibits higher oxide leakage current and lower oxide breakdown voltage.