Low frequency noise in Si(100) and Si(110) p-channel MOSFETs

摘要

The evaluation of new equipments developed at the Tohoku University and based on very low electron temperature microwave-excited high-density plasma is presented through the study of the Flicker noise. These new equipments which are working with very low electron temperature and presenting very useful features, such as an oxide growth rate regardless of the crystallographic orientation of the silicon, allow us to fabricate gate oxides of very high quality on any kind of surfaces as well as damage-free thin films. The confirmation of these features and of the quality of this technology has been confirmed from the noise measurements carried out on p-Si(100) and p-Si(110) MOS transistors that led us to the extraction of several parameters such as the trap density. Moreover, the 1/f noise study in the Si(110) transistors has been done for the first time and revealed that the noise sources are the mobility fluctuations caused by the fluctuation of the scattering mechanism in the lattice in saturation and the fluctuation of the insulator charge inducing correlated flat band voltage and fluctuation of the mobility in the linear regime. Regarding the Si(100) transistors, the Flicker noise is explained in term of mobility fluctuations in saturation and of flat band voltage fluctuation without induced fluctuation of the mobility in the linear regime, making us think that a reduction of the noise level in the case of the p-Si(110) MOS transistors could be possible. Furthermore, we showed that the technology used to fabricate the transistors on the (110) surface is already very well adapted since the interface trap density has been found to be almost regardless of the crystallographic orientation of the wafer.