Low power AlGaN/GaN MEMS pressure sensor for high vacuum application

A micro-scale pressure sensor based on suspended AlGaN/GaN heterostructure is reported with non-linear sensitivity. By sealing the cavity, vacuum sensing at various temperatures was demonstrated. To validate the proposed concept of the AlGaN/GaN vacuum sensor, a 700 µm diameter circular membrane was electrically characterized under applied...

Suspended AlGaN/GaN HEMT NO₂ Gas Sensor Integrated with Micro-heater

We developed an AlGaN/GaN high electron mobility transistor (HEMT) sensor with a tungsten trioxide (WO₃) nano-film modified gate for nitrogen dioxide (NO₂) detection. The device has a suspended circular membrane structure and an integrated micro-heater. The thermal characteristic of the Platinum (Pt) micro-heater and the...

Suppression of persistent photoconductivity AlGaN/GaN heterostructure photodetectors using pulsed heating

This paper demonstrates a method to reduce the decay time in AlGaN/GaN photodetectors by a pulsed heating mode. A suspended AlGaN/GaN heterostructure photodetector integrated with a micro-heater is fabricated and characterized under ultraviolet illumination. We have observed that the course of persistent photoconductivity was effectively...

MEMS enabled fast time-resolved X-ray diffraction characterization platform for copper nanoparticle sintering in heterogeneous integration applications

We report the design, fabrication and experimental investigation of a MEMS micro-hotplate (MHP) for fast time-resolved X-ray diffraction (TRXRD) study of Cu nanoparticle paste (nanoCu paste) sintering process. The device and its system are designed to have a 60 ms minimum time interval, uniform temperature distribution and variant gas...

Suspended tungsten trioxide (WO₃) gate AlGaN/GaN heterostructure deep ultraviolet detectors with integrated micro-heater

A suspended WO₃-gate AlGaN/GaN heterostructure photodetector integrated with a micro-heater is micro-fabricated and characterized for ultraviolet photo detection. The transient optical characteristics of the photodetector at different temperatures are studied. The 2DEG-based photodetector shows a recovery (170 s) time under 240 nm...

Characterization of an Acetone Detector based on a Suspended WO3-Gate AlGaN/GaN HEMT Integrated with Micro-heater

A suspended AlGaN/GaN high electron mobility transistor (HEMT) sensor with a tungsten trioxide (WO 3 ) nanofilm modified gate was microfabricated and characterized for ppm-level acetone gas detection. The sensor featured a suspended circular membrane structure and an integrated microheater to select the optimum working temperature. High working...

Effects of Conformal Nanoscale Coatings on Thermal Performance of Vertically Aligned Carbon Nanotubes

The high aspect ratio and the porous nature of spatially oriented forest-like carbon nanotube (CNT) structures represent a unique opportunity to engineer a novel class of nanoscale assemblies. By combining CNTs and conformal coatings, a 3D lightweight scaffold with tailored behavior can be achieved. The effect of nanoscale coatings, aluminum...

System in package (SiP) technology: Fundamentals, design and applications

Purpose: The purpose of this paper is to demonstrate a novel 3D system-in-package (SiP) approach. This new packaging approach is based on stacked silicon submount technology. As demonstrators, a smart lighting module and a sensor systems were successfully developed by using the fabrication and assembly process described in this paper. Design...

Hydrogen sulfide detection properties of Pt-gated AlGaN/GaN HEMT-sensor

AlGaN/GaN high electron mobility transistor (HEMT)-based sensors with catalytic platinum gate were micro-fabricated on commercially available epitaxial wafers and extensively characterized for ppm level hydrogen sulfide (H₂S) detection for industrial safety applications. High operating temperature above 150 °C enabled large signal...

Pt-AlGaN/GaN HEMT-sensor layout optimization for enhancement of hydrogen detection

This paper reports on the layout optimization of Pt-AlGaN/GaN HEMT-sensors for enhancing hydrogen sensor performance. Sensors with gate width and length ratios W_g/L_g from 0.25 to 10 were designed, fabricated and tested for the detection of hydrogen gas at 200 °C. Sensitivity, sensing current variation and transient...

Stretchable Binary Fresnel Lens for Focus Tuning

This paper presents a tuneable binary amplitude Fresnel lens produced by wafer-level microfabrication. The Fresnel lens is fabricated by encapsulating lithographically defined vertically aligned carbon nanotube (CNT) bundles inside a polydimethyl-siloxane (PDMS) layer. The composite lens material combines the excellent optical absorption...

Thermal characterization of carbon nanotube foam using MEMS microhotplates and thermographic analysis

Thermal material properties play a fundamental role in the thermal management of microelectronic systems. The porous nature of carbon nanotube (CNT) arrays results in a very high surface area to volume ratio, which makes the material attractive for surface driven heat transfer mechanisms. Here, we report on the heat transfer performance of...

Precision Recess of AlGaN/GaN with Controllable Etching Rate Using ICP-RIE Oxidation and Wet Etching

A method for highly controllable etching of AlGaN/GaN for the fabrication of high sensitivity HEMT based sensors is developed. The process consists of cyclic oxidation of nitride with O₂ plasma using ICP-RIE etcher followed by wet etching of the oxidized layer. Previously reported cyclic oxidation-based GaN etching obtained very...

Single-Mask Fabrication of Temperature Triggered MEMS Switch for Cooling Control in SSL System

A micro-electro-mechanical-system (MEMS) based, temperature triggered, switch is developed as a cost-effective solution for smart cooling control of solid-state-lighting systems. The switch (1.0x0.4 mm2) is embedded in a silicon substrate and fabricated with a single-mask 3D micro-machining process. The device switches on at a designed...