Fabrication

About: Fabrication is a research topic. Over the lifetime, 20475 publications have been published within this topic receiving 235676 citations.

Fabrication and characterization of freestanding 3D carbon microstructures using multi-exposures and resist pyrolysis

Abstract: We present a fabrication method for freestanding complex 3D carbon microstructures utilizing a lithogaphy step and a heating step We developed two fabrication methods for multi-level 3D SU-8 microstructures, which were used as polymer precursors in a carbonization process In one method, multiple SU-8 layers were successively coated and cross-linked In the other method, aligned partial exposures were used to control the thickness of the freestanding SU-8 layer Freestyle, freestanding carbon microstructures were fabricated by heating 3D SU-8 microstructures below 1000 °C in a nitrogen atmosphere Characterization of the pyrolysis process, through measurements such as dimensional changes, roughness, hardness, elastic modulus and resistivity, was performed for positive resists AZ5214 and AZ9260 as well as SU-8 3D carbon microstructures fabricated using our methods can be utilized for various applications such as low cost resonating microsensors and microfluidics

Fused preforms for the fabrication of photonic crystal fibers

Abstract: A novel approach for the fabrication of high-quality preforms for use in the fabrication of photonic crystal fibers is described. The preforms are fabricated in a multistep process that involves stacking a bundle with rods and (or) tubes of two dissimilar glasses, fusing the bundle, and then etching the fused bundle in acid to remove one of the two glasses. The procedure for fabrication of the fused preforms is similar to that used in the fabrication of microchannel plate glass and yields periodically spaced, uniform, round channels that extend through the length of the preform.

Fabrication of High-Q Nanobeam Photonic Crystals in Epitaxially Grown 4H-SiC.

Abstract: Silicon carbide (SiC) is an intriguing material due to the presence of spin-active point defects in several polytypes, including 4H-SiC. For many quantum information and sensing applications involving such point defects, it is important to couple their emission to high quality optical cavities. Here we present the fabrication of 1D nanobeam photonic crystal cavities (PCC) in 4H-SiC using a dopant-selective etch to undercut a homoepitaxially grown epilayer of p-type 4H-SiC. These are the first PCCs demonstrated in 4H-SiC and show high quality factors (Q) of up to ∼7000 as well as low modal volumes of <0.5 (λ/n)3. We take advantage of the high device yield of this fabrication method to characterize hundreds of devices and determine which PCC geometries are optimal. Additionally, we demonstrate two methods to tune the resonant wavelengths of the PCCs over 5 nm without significant degradation of the Q. Lastly, we characterize nanobeam PCCs coupled to luminescence from silicon vacancy point defects (V1, V2) in...

Fabrication of a Micromachined Two-Dimensional Wind Sensor by Au–Au Wafer Bonding Technology

Abstract: The design, fabrication, and performance of a micromachined 2-D wind sensor are presented. The sensor operates based on the detection of temperature and flow-dependent heat distribution on a hot sensing surface. It consists of a silicon sensing chip and a ceramic packaging substrate, in which the sensing chip is bonded to the front side of the ceramic packaging substrate through wafer-level gold bumps. The backside of the ceramic substrate provides a smooth surface for the sensor exposed to the wind flow. A silicon diaphragm was fabricated by wet etching to minimize its heat capacity, resulting in the improvement of the power consumption, response time, and resolutions. Experimental results show that the measurement of wind flow speed is demonstrated in the range from 0.5 to 40 m/s with the sensitivity more than 2.73 mW/ms-1. The sensor requires only 2 mW initial heating power, and in constant-temperature difference mode, the response time less than 1.4 s is obtained. By measuring temperature difference in two directions perpendicular to each other, the detection of direction in a full range of 360 has been achieved. The errors in the measured wind speed and direction after calibration are ±4% and ±2°, respectively.