The authors present highly selective emitters based on two-dimensional tantalum (Ta) photonic crystals, fabricated on 2 in. polycrystalline Ta substrates, for high-temperature applications, e.g., thermophotovoltaic energy conversion. In this study, a fabrication route facilitating large-area photonic crystal fabrication with high fabrication uniformity and accuracy, based on interference lithog...

Wafer-to-wafer process reproducibility during plasma etching often depends on the conditioning of the inside surfaces of the reactor. Passivation of reactor surfaces by plasma generated species, often called seasoning, can change the reactive sticking coefficients of radicals, thereby changing the composition of the radical and ion fluxes to the wafer. Ion bombardment of the walls may influence...

This work characterized the Cl2/HBr ion-enhanced plasma-surface interactions with poly-silicon as a function of the gas composition, ion energy, ion incident angle and other important process parameters. A realistic inductively coupled plasma beam apparatus capable of generating ions and neutrals representative of a real commercial etcher was constructed and utilized to simulate accurately a hi...

We present a micro electromechanical tunable capacitor with a low control voltage, a wide tuning range and adequate electrical quality factor. The device is fabricated in a single-crystalline silicon layer using deep reactive ion etching (DRIE) for obtaining high-aspect ratio (> 20) parallel combdrive structures with vertical sidewalls. The process sequence for fabrication of the devices uses o...

MEMS micropumps, based on PZT membranes have been designed and fabricated at the Microtechnology Laboratory of the University of Minnesota for use in fluid flow control, and as chemical and pressure sensors. Design, fabrication and numerical analyses of the PZT cantilever beams were presented at the MSM99, and are now extended to new MEMS devices; specifically reactive ion etched (RIE) bulk mic...

The quality of channel sidewalls resulting from through-wafer deep reactive-ion etching is analysed using scanning electron microscopy, atomic-force microscopy and interferometry. Sidewall quality and profile are highly dependent on the width of the etched channel. Channels narrower than 100 lm show generally good sidewall smoothness, though with a bowed profile. This profile leads to ion-induc...

Sidewall transfer lithography (STL) is demonstrated as a method for parallel fabrication of 2D nanostructured cellular solids in single-crystal silicon. The linear mechanical properties of four lattices (perfect and defected diamond; singly and doubly periodic honeycomb) with low effective Young’s moduli and effective Poisson’s ratio ranging from positive to negative are modelled using analytic...

Hard X-ray grating interferometry has shown promising results in phase and scattering imaging, as well as in metrology applications. Recently, the technique has been extended to two dimensions, recording the full phase gradient vector and a directional scattering signal. Here, we present a process for fabricating the key optical elements required for this technique: phase and absorption grating...

A lateral suspension, suitable for a microseismometer application, has been fabricated using deep reactive-ion etching. The critical dynamic parameters of the suspension, namely the normal modes along the compliant axis and the damping, have been determined from slow-scan imaging in an environmental scanning electron microscope. The results show the presence of an unwanted spurious mode which c...

Introduction Recent developments in silicon-based fabrication technology such as fusion bonding, deep reactive ion etching (DRIE) [1] and polyamide joints [2] are expected to enable batch fabrication of mechanically robust micromechanisms that are capable of true 3-D motion. Several MEMS structures and mechanisms have been made for motion in a plane parallel to the surface as in the case of acc...