Low-frequency noise assessment in advanced UTBOX SOI nMOSFETs with different gate dielectrics

In this paper, UTBOX nMOSFETs with different gate dielectrics have been studied based on their low-frequency noise (LFN) performance. Since LFN measurements have been successfully used as a characterization tool for determining the quality of the films, here, we have investigated the dielectric films used in state-of-the-art UTBOX devices in order to evaluate their performance and to identify the type of traps possibly introduced during the device processing.High-k gate dielectric devices have shown predominantly 1/f noise with a two-order of magnitude higher value than the conventional SiO2 ones which, consequently, results in higher density of traps in those devices. The carrier number fluctuations dominate the 1/f noise for both front and back interfaces. Due to the thin silicon film thickness there is a strong electrostatic coupling between front and back interfaces that interferes in the noise results as well as in transistor parameters. A contribution of the back interface noise source of about 14% on the measured noise in the front channel conduction was found, while the contribution of the front interface noise source is about 22% on the measured noise in the back channel conduction.The generation–recombination (GR) noise performed at different temperatures has enabled the identification of 6 types of traps and 2 unknown ones, being originated from the dry-etching or implantation damage.