Impact of strained-channel n-MOSFETs with a SiGe virtual substrate on dielectric interface quality evaluated by low frequency noise measurements

We have investigated gate and drain current noise on strained-channel n-MOSFETs with a SiGe virtual substrate and a 12 A thermally nitrided gate oxide using low frequency noise measurements. The power spectral densities (PSD) of the flat-band voltage fluctuations are extracted from both gate and drain current noise. We show that the same oxide trap density profile is involved in drain and gate low frequency noise. A comparison with standard n-MOSFET transistors with the same gate stack process is presented. The flat-band voltage PSD concept is also used to compare both technologies to show that bulk and dielectric quality of strained devices are not degraded with regard to standard n-MOSFETs.