Assembly of Silicon Nitride Channels

Fabrication of silicon based micro-channels is typically a complex process involving multiple steps such as lithography, bonding, thin film deposition, etching, surface migration etc. We present a method for the fabrication of microchannels . insired by 2D material transferring techniques, we transfer a 100 nm thick silicon nitride film on top of a silicon nitride coated chip with predefined trenches and holes to form silicon nitride microchannels and membranes

Patterning of parallel nanobridge structures by reverse nanostencil lithography using an edge-patterned stencil

We propose a new process for forming parallel nanobridge patterns by nanostencil lithography. In this process, a low-stress silicon nitride stencil with parallel nanobridge structures is fabricated by a new edge patterning technique where those nanobridges are formed simultaneously via sidewall features using the conventional photolithography and anisotropic dry etching process. After forming primary Cr patterns on the oxidized Si substrate by depositing Cr through the edge-patterned stencil, those patterns are transferred onto the underlying Si layer in a reversed manner, leading to the formation of parallel Cr nanobridge patterns on the Si substrate. Using this process, we have successfully produced 85 nm-wide parallel Cr nanobridge patterns from a stencil with 115 nm-wide nanobridge structures that was fabricated by conventional microlithography. As there is no need for advanced lithography techniques in preparing the nanobridge stencil, the combination of the edge patterning and reverse nanostencil process provides a cost-effective tool for the massive fabrication of parallel nanobridge arrays at the 100 nm scale

Reverse transfer of nanostencil patterns using intermediate sacrificial layer and lift-off process

We propose a new process by which patterns produced by nanostencil lithography can be reversed, so that the final pattern on the substrate has the same contrast (filled or empty) as that of the stencil. In this process, the stencil pattern is first formed on an intermediate sacrificial layer, and then transferred onto the underlying substrate in a reverse manner. Using this process, we can form various pattern structures that cannot be produced by the normal stencil process, such as an array of pores or multiple parallel bridges. Because a bridge in the stencil is transferred also as a bridge on the substrate, we can not only avoid the widening of a narrow bridge pattern by the stress-induced bending of the membrane, but also reduce the width of the bridge even further using the pattern blurring. Using SiO2 as an intermediate layer, we have fabricated various reversed Cr patterns on Si, including an array of 800 nm circular pores and a 100-nm-wide and 150-nm-long nanobridge

Resistless ion implantation of sub-micron scale features through nano-stencil

Resistless ion implantation of sub-micron scale features through nano-stenci

Sub-100 nm-scale Aluminum Nanowires by Stencil Lithography: Fabrication and Characterization

We present the fabrication process and electrical characterization of sub-100 nm scale Al nanowires (NWs) fabricated by stencil lithography (SL). We use a stencil with sub- 100 nm wide nanoslits patterned by focused ion beam (FIB) milling. The stencil is aligned and clamped onto a substrate containing predefined electrical contacts. Then a 60 nm-thick layer of Aluminum (Al) is deposited through the stencil producing NWs with lengths of ~1, 2 and 5 μm and widths down to 65 nm. The NWs show an ohmic behavior with values varying from 30 Ω up to 300 Ω, depending on the dimensions of the structures. We have extracted a resistivity for the Al NWs of ~10 x 10-8 Ωm. We also show that stencils can be cleaned and reused, proving that SL is a cost-efficient and scalable manufacturing method for the direct fabrication of metallic NWs on a full wafer scale

Performance Enhancement of a Graphene-Zinc Phosphide Solar Cell Using the Electric Field-Effect

The optical transparency and high electron mobility of graphene make it an attractive material for photovoltaics. We present a field-effect solar cell using graphene to form a tunable junction barrier with an Earth-abundant and low cost zinc phosphide (Zn_3P_2) thin-film light absorber. Adding a semitransparent top electrostatic gate allows for tuning of the graphene Fermi level and hence the energy barrier at the graphene-Zn_3P_2 junction, going from an ohmic contact at negative gate voltages to a rectifying barrier at positive gate voltages. We perform current and capacitance measurements at different gate voltages in order to demonstrate the control of the energy barrier and depletion width in the zinc phosphide. Our photovoltaic measurements show that the efficiency conversion is increased 2-fold when we increase the gate voltage and the junction barrier to maximize the photovoltaic response. At an optimal gate voltage of +2 V, we obtain an open-circuit voltage of V_(oc) = 0.53 V and an efficiency of 1.9% under AM 1.5 1-sun solar illumination. This work demonstrates that the field effect can be used to modulate and optimize the response of photovoltaic devices incorporating grapheme

Functional Characterization of CLPTM1L as a Lung Cancer Risk Candidate Gene in the 5p15.33 Locus

Cleft Lip and Palate Transmembrane Protein 1-Like (CLPTM1L), resides in a region of chromosome 5 for which copy number gain has been found to be the most frequent genetic event in the early stages of non-small cell lung cancer (NSCLC). This locus has been found by multiple genome wide association studies to be associated with lung cancer in both smokers and non-smokers. CLPTM1L has been identified as an overexpressed protein in human ovarian tumor cell lines that are resistant to cisplatin, which is the only insight thus far into the function of CLPTM1L. Here we find CLPTM1L expression to be increased in lung adenocarcinomas compared to matched normal lung tissues and in lung tumor cell lines by mechanisms not exclusive to copy number gain. Upon loss of CLPTM1L accumulation in lung tumor cells, cisplatin and camptothecin induced apoptosis were increased in direct proportion to the level of CLPTM1L knockdown. Bcl-xL accumulation was significantly decreased upon loss of CLPTM1L. Expression of exogenous Bcl-xL abolished sensitization to apoptotic killing with CLPTM1L knockdown. These results demonstrate that CLPTM1L, an overexpressed protein in lung tumor cells, protects from genotoxic stress induced apoptosis through regulation of Bcl-xL. Thus, this study implicates anti-apoptotic CLPTM1L function as a potential mechanism of susceptibility to lung tumorigenesis and resistance to chemotherapy

Nano-Stenciled RGD-Gold Patterns That Inhibit Focal Contact Maturation Induce Lamellipodia Formation in Fibroblasts

Cultured fibroblasts adhere to extracellular substrates by means of cell-matrix adhesions that are assembled in a hierarchical way, thereby gaining in protein complexity and size. Here we asked how restricting the size of cell-matrix adhesions affects cell morphology and behavior. Using a nanostencil technique, culture substrates were patterned with gold squares of a width and spacing between 250 nm and 2 µm. The gold was functionalized with RGD peptide as ligand for cellular integrins, and mouse embryo fibroblasts were plated. Limiting the length of cell-matrix adhesions to 500 nm or less disturbed the maturation of vinculin-positive focal complexes into focal contacts and fibrillar adhesions, as indicated by poor recruitment of α5-integrin. We found that on sub-micrometer patterns, fibroblasts spread extensively, but did not polarize. Instead, they formed excessive numbers of lamellipodia and a fine actin meshwork without stress fibers. Moreover, these cells showed aberrant fibronectin fibrillogenesis, and their speed of directed migration was reduced significantly compared to fibroblasts on 2 µm square patterns. Interference with RhoA/ROCK signaling eliminated the pattern-dependent differences in cell morphology. Our results indicate that manipulating the maturation of cell-matrix adhesions by nanopatterned surfaces allows to influence morphology, actin dynamics, migration and ECM assembly of adhering fibroblasts