Research On Low-frequency Noise Model Of Tunneling For Mosfets With High-k Gate Dielectrics

In the MOS devices, the use of the hafnium-based high-k dielectric can apparent reduce the gate leakage current, but also can lead to a greater amount of reliability problems due to the relatively high defect density. In order to improve the quality of the high-k dielectric, it is important to capture deeply the nature of defects, such as spatial and energy distribution feature of defects.Noise can respond effectively the potential defects which can make the device failure. The noise changes more sensitive than other electrical parameters, so it has been widely used to study the trap properties of semiconductors. United noise model is the most successful one which characterizes the noise of the MOSFET, but using it to abstract parameters of high-k MOS device brings obvious errors. So this model can not been used to characterize the noise of the high-k MOS devices. Thus,it is necessary to build a new accurate low frequency noise model, and this can improve the understand of defects, optimize device performancend enhance device reliability.In recent years, the literature has widely studied the noise characteristics of high-k dielectrics and high-k gate stack low-frequency noise model which is based on the original uniform noise model. But this model only considers direct tunneling mechanism, the study shows resonant tunneling mechanism existence besides the direct tunneling. However,all of the available low frequency noise models consider only direct tunneling without resonant tunneling, so these models must be imperfect. This article is a combination of direct tunneling and resonant tunneling to establish 1/f noise model. Following will show the main work in the article:Frist, the present situation of high-k MOSFET low frequency model has been researched. We discuss how to build the low frequency noise model based direct tunneling mechanism and how to modify the model to apply to new type devices. According to the feature of high-k gate stack structure and defect characteristics, we find these models problematic. Second, the effect of carriers capture and emission process on drain current noise has been research, further we discuss the feasible tunneling process and draw the conclusion that there is resonant tunneling mechanism except direct tunneling mechanism and give the theoretical simulation and experimental evidence. Then we establish physical model of the defect exchange the channel carriers though resonant tunneling mechanism, get resonant tunneling coefficient of double layer structure and character time constant under this model, and verify and discuss this model. Last, we propose the idea of building low frequency model and establish the low frequency model based on resonant tunneling and direct tunneling mechanism for the high-k MOSFET device. This lays theoretical foundation which makes the noise a powerful tool to characterize and probe defects in high-K MOS stacks.