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Nanoelectromechnical system (NEMS)is seen as one of the most promisingcandidates for next generation extreme low power electronics thatcan operate as a versatile switch/memory/sensor/display element. Oneof the main challenges toward this goal lies in the fabrication difficultiesof ultrascaled NEMS required for high density integrated circuits.It is generally understood that fabricating and operating a NEMS withan airgap below a few nanometer will be extremely challenging dueto surface roughness, nonideal forces, tunneling, etc. Here, we showthat by cascading a NEMS with a ferroelectric capacitor, operatingin the negative capacitance regime, the effective airgap can be reducedby almost an order of magnitude, without the need to reducethe airgap physically. This would not only reduce the pull-involtage to sub-1 V regime, but also would offer a set of characteristicswhich are difficult/impossible to achieve otherwise. For example,one can reduce/increase the classical travel range, flip the traditionalstable-unstable regime of the electrode, get a negative pull-out voltage,and thus, center the hysteresis around zero volt. Moreover, one canalso operate the combination as an effective ferroelectric memorywith much reduced switching voltages. These characteristics promisedramatic saving in power for NEMS-based switching, memory, and otherrelated applications. [ABSTRACT FROM AUTHOR]

The crucial role of nanocrystalline morphology in stabilizing the ferroelectric orthorhombic (o)-phase in doped-hafnia films is achieved via chemical solution deposition (CSD) by intentionally retaining carbonaceous impurities to inhibit grain growth. However, in the present study, large-grained (>100 nm) La-doped HfO 2 (HLO) films are grown directly on silicon by adopting engineered water-diluted precursors with a minimum carbonaceous load and excellent shelf life. The o-phase stabilization is accomplished through a well-distributed La dopant, which generates uniformly populated oxygen vacancies, eliminating the need for oxygen-scavenging electrodes. These oxygen-deficient HLOs show a maximum remnant polarization of 37.6 μC/cm 2 (2 P r ) without wake-up and withstand large fields (>6.2 MV/cm). Furthermore, CSD-HLO in series with Al 2 O 3 improves switching of MOSFETs (with an amorphous oxide channel) based on the negative capacitance effect. Thus, uniformly distributed oxygen vacancies serve as a standalone factor in stabilizing the o-phase, enabling efficient wake-up-free ferroelectricity without the need for nanostructuring, capping stresses, or oxygen-reactive electrodes.

Nanobiosensors based on silicon nanowire field effect transistors offer advantages of low cost, label-free detection, and potential for massive parallelization. As a result, these sensors have often been suggested as an attractive option for applications in point-of-care (POC) medical diagnostics. Unfortunately, a number of performance issues, such as gate leakage and current instability due to fluid contact, have prevented widespread adoption of the technology for routine use. High-k dielectrics, such as hafnium oxide (HfO(2)), have the known ability to address these challenges by passivating the exposed surfaces against destabilizing concerns of ion transport. With these fundamental stability issues addressed, a promising target for POC diagnostics and SiNWFETs has been small oligonucleotides, more specifically, microRNA (miRNA). MicroRNAs are small RNA oligonucleotides which bind to mRNAs, causing translational repression of proteins, gene silencing, and expressions are typically altered in several forms of cancer. In this paper, we describe a process for fabricating stable HfO(2) dielectric-based silicon nanowires for biosensing applications. Here we demonstrate sensing of single-stranded DNA analogues to their microRNA cousins using miR-10b and miR-21 as templates, both known to be upregulated in breast cancer. We characterize the effect of surface functionalization on device performance using the miR-10b DNA analogue as the target sequence and different molecular weight poly-l-lysine as the functionalization layer. By optimizing the surface functionalization and fabrication protocol, we were able to achieve <100 fM detection levels of the miR-10b DNA analogue, with a theoretical limit of detection of 1 fM. Moreover, the noncomplementary DNA target strand, based on miR-21, showed very little response, indicating a highly sensitive and highly selective biosensing platform.