We developed a generalized technique to characterize polymer-nanopore interactions via single channel ionic current measurements. Physical interactions between analytes, such as DNA, proteins or synthetic polymers, and a nanopore cause multiple discrete states in the ionic current. We modeled the transitions of the ionic current to individual states with an equivalent electrical circuit of the nanopore system, which allowed us to describe the system response. This enables the estimation of short-lived states in single-molecule nanopore data that are presently not characterized by existing analysis techniques. Our approach considerably improves the range and resolution of single-molecule characterization with nanopores. For example, we characterized the residence times of molecules in the nanopore that are three times shorter than those estimated with existing algorithms. Because the molecule’s residence time follows an exponential distribution, we recover nearly 20-fold more events per unit time that can be used for analysis. Furthermore, the measurement range was extended from 11 monomers to as few as 8. Finally, we apply this technique to recover a known sequence of single stranded DNA from previously published ion channel recordings, identifying discrete current states with sub-picoampere resolution.

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Recently, 1/f and random telegraph noise (RTN) studies have been used to infer information about bulk dielectric defects' spatial and energetic distributions. These analyses rely on a noise framework which involves charge exchange between the inversion layer and the bulk dielectric defects via elastic tunneling. In this study, we extracted the characteristic capture and emission time constants from RTN in highly scaled nMOSFETs and showed that they are inconsistent with the elastic tunneling picture dictated by the physical thickness of the gate dielectric (1.4 nm). Consequently, our results suggest that an alternative model is required and that a large body of the recent RTN and 1/f noise defect profiling literature very likely needs to be re-interpreted.

Free electron concentration and carrier mobility measurements on 4H–SiC metal-oxide-semiconductor inversion layers are reported in this article. The key finding is that in state-of-the-art nitrided gate oxides, loss of carriers by trapping no longer plays a significant role in the current degradation under heavy inversion conditions. Rather, it is the low carrier mobility (maximum∼60 cm2 V−1 s−1) that limits the channel current. The measured free carrier concentration is modeled using the charge-sheet model and the mobility is modeled by existing mobility models. Possible mobility mechanisms have been discussed based on the modeling results.

The ultrafast measurements of polarization switching dynamics on ferroelectric (FE) and antiferroelectric (AFE) hafnium zirconium oxide (HZO) are studied. The transient current during the polarization switching process is probed directly on the nanosecond scale. The switching time is determined to be as fast as 10 ns to reach fully switched polarization with characteristic switching times of 5.4 ns for FE HZO and 4.5 ns for AFE HZO by the nucleation limited switching model. The limitation by the parasitic effect on capacitor charging is found to be critical in the correct and accurate measurements of intrinsic polarization switching speed of HZO.

An entirely physical model is proposed to explain a wide range of seemingly conflicting observations of plasma-charging damage. Unlike other authors who largely ignored the role of substrate potential, we carefully track both the gate and the substrate potentials to explain the origin of the electric field developed across the thin oxide during plasma exposure. Central to this model is the fact that the surface floating potential tracks the plasma potential. Thus a nonuniform plasma drives the gate potential to a nonuniform distribution. Another important idea of this model is the continued adjustment by both the gate and the substrate of their potentials to satisfy the charge balance requirement of plasma system. The interaction between saturated ion-current, asymmetric electron-current, and the Fowler–Nordheim tunneling current produces a complex dynamic for the movements of the gate and the substrate potentials. This complex behavior of the gate and the substrate potential allows many of the reported observations in the literature to be explained logically. We explored three types of charging effect and their damage characteristics. They are dc effect, ac effect, and transient effect. The separation of dc and ac effect is artificial. They exist simultaneously and add to each other to cause more serious damage than by themselves. The model predicts antenna effects from all three types of charging effects. Unique to the ac antenna effect are saturation behavior, the oxide thickness ratio dependence, and the rf bias-frequency dependence. The effect of ON/OFF transient is explored quantitatively using the concept of effective exposed substrate area. The combination of large antenna ratio and rapid turn-off of plasma causes severe damage to gate-oxide. Magnetic field in general will worsen the charging damage. The reason for that is explained. Plasma uniformity is the most important factor governing charging damage, but is not the only factor. Plasma uniformity extending beyond the edge of the wafer is important. Mere showing that the plasma is uniform across the most part of the wafer is misleading.

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We utilize low-frequency noise measurements to examine the sub-threshold voltage (sub-V TH ) operation of highly scaled devices. We find that the sub-V TH low-frequency noise is dominated by random telegraph noise (RTN). The RTN is exacerbated both by channel dimension scaling and reducing the gate overdrive into the sub-V TH regime. These large RTN fluctuations greatly impact circuit variability and represent a troubling obstacle that must be solved if sub-V TH operation is to become a viable solution for low-power applications.