On the beneficial impact of tensile-strained silicon substrates on the low-frequency noise of n-channel metal-oxide-semiconductor transistors

Abstract

The low-frequency noise in n-channel metal-oxide-semiconductor field-effect transistors, fabricated on strained silicon (SSi) substrates has been investigated and compared with the results obtained on silicon reference wafers. The strained silicon was deposited on a thin strain-relaxed SiGe buffer layer. A 2-nm SiO2 layer was used as a gate dielectric. It is shown that a factor of 2–3 lower noise can be found in the SSi devices at a frequency f=10Hz, which appears to be correlated with the low-field mobility. This is interpreted in terms of the impact of the biaxial tensile strain on the gate oxide defectiveness.