OH dangling-bond saturation and dielectric function effects in ultra-scaled SNW-FETs

State-of-the-art analyses of the electronic properties of silicon nanowires (SNWs) are usually based on H-saturated interface bonds. However, only a minority of bonds are saturated by H at the typical Si-SiO2 interface. Moreover, the variations of the dielectric function with the lateral size of the SNW have not been addressed. In this work, we investigate the electronic properties and I-V characteristics of a 7x7 SNW with OH-saturated dangling-bonds and of a 5x5 SNW ac-counting for the variation of the dielectric function. To this purpose, we use a new approach to the computation of quantum transport which accounts for the complete periodic shape of the 1DEG energy subbands for the 1D transport. The main findings of our analysis are: i) the band structures of SNW with dangling-bonds saturated with H or OH show relevant differences in the shape and energy of the subbands, leading to different transport characteristics; ii) the calculated dielectric function in the 5x5 SNW is about 50% smaller with respect to bulk, which leads to a 20% reduction of the ON-current.