Alkali-free glasses show immense promise for the development of high-energy density capacitors. The high breakdown strengths on single-layer sheets of glass suggest the potential for improved energy densities over existing state-of-the art polymer capacitors. In this paper, we demonstrate the ability to package thin glass to make solid-state capacitors. Individual layers are bonded using epoxy, leading to capacitors that exhibit stable operation over the temperature range -55 °C to +65 °C. This fabrication approach is scalable and allows for proof testing individual layers prior to incorporation of the stack, providing a blueprint for the fabrication of high-energy density capacitors.
We have developed and characterized novel in-situ corrosion sensors to monitor and quantify the corrosive potential and history of localized environments. Embedded corrosion sensors can provide information to aid health assessments of internal electrical components including connectors, microelectronics, wires, and other susceptible parts. When combined with other data (e.g. temperature and humidity), theory, and computational simulation, the reliability of monitored systems can be predicted with higher fidelity.
We report on the development of a highly miniaturized vacuum package for use in an atomic clock utilizing trapped ytterbium-171 ions. The vacuum package is approximately 1 cm3 in size and contains a linear quadrupole RF Paul ion trap, miniature neutral Yb sources, and a non-evaporable getter pump. We describe the fabrication process for making the Yb sources and assembling the vacuum package. To prepare the vacuum package for ion trapping, it was evacuated, baked at a high temperature, and then back filled with a helium buffer gas. Once appropriate vacuum conditions were achieved in the package, it was sealed with a copper pinch-off and was subsequently pumped only by the non-evaporable getter. We demonstrated ion trapping in this vacuum package and the operation of an atomic clock, stabilizing a local oscillator to the 12.6 GHz hyperfine transition of 171Y b+. The fractional frequency stability of the clock was measured to be 2 × 10-11/τ1/2.
Many microfabrication techniques are being developed for applications in microelectronics, microsensors, and micro-optics. Since the advent of microcomponents, designers have been forced to modify their designs to include limitations of current technology, such as the inability to make three-dimensional structures and the need for piece-part assembly. Many groups have successfully transferred a wide variety of patterns to both two-dimensional and three-dimensional substrates using microcontact printing. Microcontact printing is a technique in which a self-assembled monolayer (SAM) is patterned onto a substrate by transfer printing. The patterned layer can act as an etch resist or a foundation upon which to build new types of microstructures. We created a gold pattern with features as small as 1.2 {micro}m using microcontact printing and subsequent processing. This approach looks promising for constructing single-level structures such as microelectrode arrays and sensors. It can be a viable technique for creating three-dimensional structures such as microcoils and microsprings if the right equipment is available to achieve proper alignment, and if a means is available to connect the final parts to other components in subsequent assembly operations. Microcontact printing provides a wide variety of new opportunities in the fabrication of microcomponents, and increases the options of designers.
Ceramic interconnect technology has been adapted to new structures. In particular, the ability to customize processing order and material choices in Low Temperature Cofired Ceramic (LTCC) has enabled new features to be constructed, which address needs in MEMS packaging as well as other novel structures. Unique shapes in LTCC permit the simplification of complete systems, as in the case of a miniature ion mobility spectrometer (IMS). In this case, a rolled tube has been employed to provide hermetic external contacts to electrodes and structures internal to the tube. Integral windows in LTCC have been fabricated for use in both lids and circuits where either a short term need for observation or a long-term need for functionality exists. These windows are fabricated without adhesive, are fully compatible with LTCC processing, and remain optically clear. Both vented and encapsulated functional volumes have been fabricated using a sacrificial material technique. These hold promise for self-assembly of systems, as well as complex internal structures in cavities, micro fluidic and optical channels, and multilevel integration techniques. Separation of the burnout and firing cycles has permitted custom internal environments to be established. Existing commercial High Temperature Cofired Ceramic (HTCC) and LTCC systems can also be rendered to have improved properties. A rapid prototyping technique for patterned HTCC packages has permitted prototypes to be realized in a few days, and has further applications to micro fluidics, heat pipes, and MEMS, among others. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.