Dopamine is a neurotransmitter that modulates arousal and motivation in humans and animals. It plays a central role in the brain "reward" system. Its dysregulation is involved in several debilitating disorders such as addiction, depression, Parkinson's disease, and schizophrenia. Dopamine neurotransmission and its reuptake in extracellular space takes place with millisecond temporal and nanometer spatial resolution. Novel nanoscale electrodes are needed with superior sensitivity and improved spatial resolution to gain an improved understanding of dopamine dysregulation. We report on a scalable fabrication of dopamine neurochemical probes of a nanostructured glassy carbon that is smaller than any existing dopamine sensor and arrays of more than 6000 nanorod probes. We also report on the electrochemical dopamine sensing of the glassy carbon nanorod electrode. Compared with a carbon fiber, the nanostructured glassy carbon nanorods provide about 2× higher sensitivity per unit area for dopamine sensing and more than 5× higher signal per unit area at low concentration of dopamine, with comparable LOD and time response. These glassy carbon nanorods were fabricated by pyrolysis of a lithographically defined polymeric nanostructure with an industry standard semiconductor fabrication infrastructure. The scalable fabrication strategy offers the potential to integrate these nanoscale carbon rods with an integrated circuit control system and with other complementary metal oxide semiconductor (CMOS) compatible sensors.

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Plasmas have been widely utilized to pattern various materials, from metals to semiconductors and oxides to polymers, for a vast array of applications. The interplay between physical, chemical and material properties that comprises the backbone of plasma etching is discussed in this perspective paper, with a focus on the needed tools and approaches to address the challenges facing plasma etching and to realize the desired pattern transfer fidelity at the nanoscale.

The use of a water-soluble polymer for area selective atomic layer deposition (ALD) with microcontact printing (μCP) has been studied. Polymethacrylamide (PMAM) was spin-coated and patterned onto substrates of silicon by μCP , generating patterns down to 2μm in size. The resist properties were tested against Pt ALD. The results show that films of Pt were grown selectively on the PMAM-free regions and significantly blocked in the presence of the polymer. Scanning electron microscopy and scanning Auger electron spectroscopy showed sharp pattern transfer of PMAM and good propagation of the pattern into the Pt layer. The PMAM layer was simply removed just by dipping in water. After the removal process, the PMAM-coated surface exhibited the same properties as the original SiO2 surface. The use of PMAM as an ALD resist offers good selectivity and high spatial resolution and provides a new, convenient route toward achieving spatially patterned film growth.

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The invention of the transistor followed by more than 60 years of aggressive device scaling and process integration has enabled the global information web and subsequently transformed how people communicate and interact. The principles and practices built upon chemical processing of materials on silicon have been widely adapted and applied to other equally important areas, such as microfluidic systems for chemical and biological analysis and microscale energy storage solutions. The challenge of continuing these technological advances hinges on further improving the performance of individual devices and their interconnectivity while making the manufacturing processes economical, which is dictated by the materials' innate functionality and how they are chemically processed. In this review, we highlight challenges in scaling up the silicon wafers and scaling down the individual devices as well as focus on needs and challenges in the synthesis and integration of multifunctional materials.

Surface oxide formation inhibiting the etch of a tantalum nitride (TaN) film was controlled through step pressure modulation and H2 addition in a Cl2/Ar based plasma-assisted cyclic etch process. Sources contributing to the oxidation of the film included the mask materials, specifically the silicon-containing antireflective coating, as measured by optical emission spectroscopy. Surface analysis of etched films by secondary ion mass spectroscopy showed the presence of a modified surface layer ∼2 nm thick with localized oxygen concentrations 0.02 and 0.003 that of the control sample (without and with H2 addition, respectively). Reduced Ta–O bonding observed via x-ray photoelectron spectroscopy as a result of H2 addition was found to enhance etch rate uniformity of both blanket and patterned films. Minimization of redeposited oxidized TaN on the mask sidewalls of patterned samples was achieved using this etch process and by controlling the lithographic stack composition.