Microheater

About: Microheater is a research topic. Over the lifetime, 814 publications have been published within this topic receiving 12478 citations.

Use of Microhotplate Arrays as Microdeposition Substrates for Materials Exploration

Abstract: An approach for high-throughput rapid screening of chemical vapor deposition (CVD) materials using micromachined silicon microheater arrays is described. To illustrate this approach, titanium dioxide was deposited by CVD, using titanium(IV) nitrate and titanium(IV) isopropoxide at temperatures between 130 and 815 °C. Deposition was confined to the microhotplate elements within 4- and 16-element arrays. Film microstructure was examined by scanning electron microscopy. In situ electrical measurements were made with integrated microcontacts during the deposition of TiO2 using titanium(IV) isopropoxide. A novel approach using temperature-programmed deposition with temperature ramp rates up to 800 °C/s was also employed for microstructure modification during deposition. Additionally, the steep temperature gradients present on the microhotplate supports have been demonstrated to provide an excellent platform for investigating temperature-dependent microstructures.

Development of a low-power thick-film gas sensor deposited by screen-printing technique onto a micromachined hotplate

Abstract: We report on the design, implementation and characterisation of a thick-film gas sensor deposited for the first time by screen-printing technique onto a micromachined hotplate, the microheater maintains a film temperature as high as 400°C with 2 was achieved by computer-aided screen-printing. The films were then fired through the microheater itself to guarantee thermodynamic stability for long time exploitation. The response of the device to CO, CH 4 and NO 2 at concentrations typical for indoor and outdoor applications was recorded by measuring the film resistance through ultra high impedance CMOS circuit.

Integrated and microheater embedded gas sensor array based on the polymer composites dispensed in micromachined wells

Abstract: This paper reports a new fabrication method and a performance of miniaturized and temperature-controllable gas sensor array constructed on 5 in. double side polished (1 0 0) silicon wafer. The films of polymer-carbon black composite were used as gas sensors. Both silicon process and bulk micromachining technology were employed to fabricate sensor array equipped with an interdigitated electrode pair, microheater, and micromachined well of an area of 2 mm ×2 mm. During dispensing a polymer composite–solvent solution on the electrode, micromachined well helped the sensor film be placed in a constrained area and be formed reproducibly from a constant volume of the polymer composite–solvent solution. The dimension of a sensor array chip consisting of 16 separate sensors is 30 mm ×14 mm. The sensors of polymer-carbon black composite responded diversely when they were dispensed in micromachined wells and exposed to various chemical vapors. Principal component analysis (PCA) clearly demonstrated that the gas sensor array could identify various chemical vapors. Pt microheater consumed 7 mW to heat sensor film at the operating temperature of 40 °C, and temperature reached a steady maximum value promptly because of its small heat capacity and effective thermal isolation. The electrical resistance of polymer composite sensor and the partition coefficients for sensor–vapor interactions showed to be considerably affected by the substrate temperature.

A Novel Two-Axis CMOS Accelerometer Based on Thermal Convection

Abstract: Accelerometers based on thermal convection use a tiny bubble of heated air and pairs of temperature sensors hermetically sealed inside the sensor package cavity. In this paper, we successfully design and fabricate a novel thermal-bubble-based micromachined accelerometer with the advantages of minimized solid thermal conductance and higher sensitivity. The proposed accelerometer consists of a microheater and two pairs of thermopiles floating over an etched cavity and is constructed by our proposed microlink structure. Two-dimensional acceleration detection is easily realized using the microlink structure, and it can be applied to the technology of inclinometers, anemometers, and flowmeters. The heater and thermopiles are connected by netlike microlink structures, which enhance the structure and greatly reduce the solid heat flow from the heater to the hot junctions of the thermopiles. The samples are fabricated by the TSMC 0.35-mum 2P4M CMOS process, which has been provided by the national chip implementation center (CIC). Our design has proved to be applicable for commercial batch production with outstanding strong structures and uniform quality. We measure the output signal by inclining the sensor to evaluate the performance of this accelerometer. The best sensitivity of 22 muV/g was obtained from acceleration versus output voltage under several experimental conditions.

Microfabricated microconcentrator for sensors and gas chromatography

Abstract: Devices for enhancing the sensitivity of a microsensor or any other micro device by providing on-line preconcentration. Microconcentrators that can be integrated with a sensor or a micromachined GC to enhance the signal to noise ratio can include a miniaturized sorbent trap fabricated on a microchip. The microconcentrator can be made on a silicon substrate so that a sensor can be integrated on the same chip. The microconcentrator is composed of at least one microchannel lined with a microheater for in-situ heating. Preconcentration may be achieved on a thin-film polymeric layer deposited above the heater in the microchannel. Rapid heating by the channel heater generates a “desorption pulse” to be injected into a detector or a sensor.