An apparatus may include a semiconductor chip and a fluidics assembly. The semiconductor chip has an array of wells and an array of sensors and each sensor of the array of sensors is in fluid communication with a well of the array of wells. The fluidics assembly is located on top of the semiconductor chip and is configured to deliver fluids to the semiconductor chip. The fluidics assembly includes a flow expansion chamber configured to introduce the fluids, an outlet portion configured to pipe out the fluids, and a flow chamber portion. The flow chamber portion is configured to allow the fluids to flow from the flow expansion chamber to the outlet portion and to allow the fluids to interact along the way with material in the array of wells. The flow expansion chamber has a curved wall at the top or bottom so that the height of the flow expansion chamber at the center is less than at the walls that restrict the fluids to the left and right.

Methods and apparatus for measuring analytes using large scale fet arrays

Methods and apparatus relating to FET arrays including large FET arrays for monitoring chemical and/or biological reactions such as nucleic acid sequencing-by-synthesis reactions. Some methods provided herein relate to improving signal (and also signal to noise ratio) from released hydrogen ions during nucleic acid sequencing reactions.

Methods and apparatus for measuring analytes

Dusty plasmas are ubiquitous in low-temperature laboratory discharges as well as in the near-earth environment, planetary rings, and interstellar spaces. In this paper, updated knowledge of fundamentals of collective dust-plasma interactions and several novel phenomena are presented that have been observed in laboratories and in space dusty plasmas. Mechanisms that are responsible for the charging of dust grains are discussed, and the fact that the dust charge perturbation is a new dynamical variable in a dusty plasma. The underlying physics of different forces that act on a charged dust grain is reviewed. In dusty plasmas, there are new attractive forces (e.g., due to wakefield and ion focusing effects and dipole-dipole interactions between unevenly charged dust rods). Furthermore, in the presence of an ensemble of charged dust grains, there are collective dust-plasma interactions featuring new waves (e.g., the dust acoustic wave, the dust ion-acoustic wave, the dust lattice wave, etc.), new instabilities, and coherent nonlinear structures (dust acoustic and dust ion-acoustic shocks, dust voids, and dust vortices), which are also discussed. Theoretical models for numerous collective dust-plasma interactions are compared with existing observations from laboratories and space environments.

Colloquium : Fundamentals of dust-plasma interactions

Methods and apparatuses relating to large scale FET arrays for analyte detection and measurement are provided. ChemFET (e.g., ISFET) arrays may be fabricated using conventional CMOS processing techniques based on improved FET pixel and array designs that increase measurement sensitivity and accuracy, and at the same time facilitate significantly small pixel sizes and dense arrays. Improved array control techniques provide for rapid data acquisition from large and dense arrays. Such arrays may be employed to detect a presence and/or concentration changes of various analyte types in a wide variety of chemical and/or biological processes.

Methods and apparatus for detecting molecular interactions using FET arrays

The ferroelectricity in fluorite-structure oxides such as hafnia and zirconia has attracted increasing interest since 2011 They have various advantages such as Si-based complementary metal oxide semiconductor-compatibility, matured deposition techniques, a low dielectric constant and the resulting decreased depolarization field, and stronger resistance to hydrogen annealing However, the wake-up effect, imprint, and insufficient endurance are remaining reliability issues Therefore, this paper reviews two major aspects: the advantages of fluorite-structure ferroelectrics for memory applications are reviewed from a material’s point of view, and the critical issues of wake-up effect and insufficient endurance are examined, and potential solutions are subsequently discussed

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/3DB31D1931EA9955AF5E300BC33891D6/S2159685918001751a.pdf/div-class-title-review-and-perspective-on-ferroelectric-hfo-span-class-sub-2-span-based-thin-films-for-memory-applications-div.pdf

Review and perspective on ferroelectric HfO2-based thin films for memory applications

We introduce using sputtered aluminum oxide (alumina) as a resilient etch mask for fluorinated silicon reactive ion etches. Achieving selectivity of 5000:1 for cryogenic silicon etching and 68:1 for SF_6/C_4F_8 silicon etching, we employ this mask for fabrication of high-aspect-ratio silicon micropillars and nanopillars. Nanopillars with diameters ranging from below 50 nm up to several hundred nanometers are etched to heights greater than 2 µm. Micropillars of 5, 10, 20, and 50 µm diameters are etched to heights of over 150 µm with aspect ratios greater than 25. Processing and characterization of the sputtered alumina is also discussed.

http://iopscience.iop.org/article/10.1088/0957-4484/20/25/255305/pdf

Alumina Etch Masks for Fabrication of High-Aspect-Ratio Silicon Micropillars and Nanopillars

Pyroelectric coefficients were measured for 20 nm thick crystalline hafnium zirconium oxide (Hf1-xZrxO2) thin films across a composition range of 0 ≤ x ≤ 1. Pyroelectric currents were collected near room temperature under zero applied bias and a sinusoidal oscillating temperature profile to separate the influence of non-pyroelectric currents. The pyroelectric coefficient was observed to correlate with zirconium content, increased orthorhombic/tetragonal phase content, and maximum polarization response. The largest measured absolute value was 48 μCm−2 K−1 for a composition with x = 0.64, while no pyroelectric response was measured for compositions which displayed no remanent polarization (x = 0, 0.91, and 1).

Pyroelectric response in crystalline hafnium zirconium oxide (Hf1-xZrxO2) thin films

Ferroelectric hafnium zirconium oxide holds great promise for a broad spectrum of complementary metal-oxide-semiconductor (CMOS) compatible and scaled microelectronic applications, including memory, low-voltage transistors, and infrared sensors, among others. An outstanding challenge hindering the implementation of this material is polarization instability during field cycling. In this study, the nanoscale phenomena contributing to both polarization fatigue and wake-up are reported. Using synchrotron X-ray diffraction, the conversion of non-polar tetragonal and polar orthorhombic phases to a non-polar monoclinic phase while field cycling devices comprising noble metal contacts is observed. This phase exchange accompanies a diminishing ferroelectric remanent polarization and provides device-scale crystallographic evidence of phase exchange leading to ferroelectric fatigue in these structures. A reduction in the full width at half-maximum of the superimposed tetragonal (101) and orthorhombic (111) diffraction reflections is observed to accompany wake-up in structures comprising tantalum nitride and tungsten electrodes. Combined with polarization and relative permittivity measurements, the observed peak narrowing and a shift in position to lower angles is attributed, in part, to a phase exchange of the non-polar tetragonal to the polar orthorhombic phase during wake-up. These results provide insight into the role of electrodes in the performance of hafnium oxide-based ferroelectrics and mechanisms driving wake-up and fatigue, and demonstrate a non-destructive means to characterize the phase changes accompanying polarization instabilities.

Phase-Exchange-Driven Wake-Up and Fatigue in Ferroelectric Hafnium Zirconium Oxide Films.

By using a dry etch chemistry which relies on the highly preferential etching of silicon, over that of gallium (Ga), we show resist-free fabrication of precision, high aspect ratio nanostructures and microstructures in silicon using a focused ion beam (FIB) and an inductively coupled plasma reactive ion etcher (ICP-RIE). Silicon etch masks are patterned via Ga^+ ion implantation in a FIB and then anisotropically etched in an ICP-RIE using fluorinated etch chemistries. We determine the critical areal density of the implanted Ga layer in silicon required to achieve a desired etch depth for both a Pseudo Bosch (SF_6/C_4F_8) and cryogenic fluorine (SF_6/O_2) silicon etching. High fidelity nanoscale structures down to 30 nm and high aspect ratio structures of 17:1 are demonstrated. Since etch masks may be patterned on uneven surfaces, we utilize this lithography to create multilayer structures in silicon. The linear selectivity versus implanted Ga density enables grayscale lithography. Limits on the ultimate resolution and selectivity of Ga lithography are also discussed.

https://iopscience.iop.org/article/10.1088/0957-4484/21/24/245303/pdf

Ga+ beam lithography for nanoscale silicon reactive ion etching

The physical structuring of silicon is one of the cornerstones of modern microelectronics and integrated circuits. Typical structuring of silicon requires generating a plasma to chemically or physically etch silicon. Although many tools have been created to do this, the most finely honed tool is the Inductively Couple Plasma Reactive Ion Etcher. This tool has the ability to finesse structures from silicon unachievable on other machines. Extracting structures such as high aspect ratio silicon nanowires requires more than just this tool, however. It requires etch masks which can adequately protect the silicon without interacting with the etching plasma and highly tuned etch chemistry able to protect the silicon structures during the etching process. In the work presented here, three highly tuned etches for silicon, and its oxide, will be described in detail. The etches presented utilize a type of etch chemistry which provides passivation while simultaneously etching, thus permitting silicon structures previously unattainable. To cover the range of applications, one etch is tuned for deep reactive ion etching of high aspect ratio micro-structures in silicon, while another is tuned for high aspect ratio nanoscale structures. The third etch described is tuned for creating structures in silicon dioxide. Following the description of these etches, two etch masks for silicon will be described. The first mask will detail a highly selective etch mask uniquely capable of protecting silicon for both etches described while being compatible with mainstream semiconductor fabrication facilities. This mask is aluminum oxide. The second mask detailed permits for a completely dry lithography on the micro and nanoscale, FIB implanted Ga etch masks. The third chapter will describe the fabrication and in situ electrical testing of silicon nanowires and nanopillars created using the methods previously described. A unique method for contacting these nanowires is also described which has enabled investigation into the world of nanoelectronics. The fourth and final chapter will detail the design and construction of high magnetic fields and integrated planar microcoils, work which was enabled by the etching detailed here. This research was directed towards creation of a portable NMR machine.

Michael David Henry

Papers

Alumina Etch Masks for Fabrication of High-Aspect-Ratio Silicon Micropillars and Nanopillars

Pyroelectric response in crystalline hafnium zirconium oxide (Hf1-xZrxO2) thin films

Phase-Exchange-Driven Wake-Up and Fatigue in Ferroelectric Hafnium Zirconium Oxide Films.

Ga+ beam lithography for nanoscale silicon reactive ion etching

ICP Etching of Silicon for Micro and Nanoscale Devices