Microheater

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

Ambient Temperature Compensation of Thin Film Pirani Vacuum Sensor

Abstract: A thin film Pirani vacuum sensor having a single microheater and two diode-thermistors (Th-A and Th-B) composed of pn junction diodes on the micro-air-bridge (MAB) is fabricated by micromachining technologies. A method to eliminate the ambient temperature effects based on double pulse-heating (pulse duration: 125ms) up to two different temperatures, Th and Tl, above the room temperature in vacuum sensing is proposed. Pulse-heating has also a merit to prevent temperature increase of the sensor chip. It is demonstrated that the Pirani gauge with a cantilever type MAB structure can almost compensate the ambient temperature effects by double pulse-heating. A method to correct the errors due to the non-linearity in the I-T relationship of the diode-thermistor as a very sensitive temperature sensor is also described.

Heat conductivity measuring method

Abstract: PURPOSE:To measure the heat conductivity of a thin film by arranging heat sources between the thin film and its substrate at constant intervals and measuring the temperature variation of the surface of the thin film while the heat sources generate heat periodically. CONSTITUTION:The microheaters 3 are embedded between the substrate 2 and thin film 1 to be measured at the constant gap intervals and generate heat at a specific period to separate thermal influence between the thin film 1 and substrate 2; and a radiation thermometer is used to measure the phases of temperature amplitudes on the gaps of the heaters embedded in the surface of the thin film 1, the phase difference from the phase of microheater heating is found to calculate heat diffusivity from the phase difference, and the result is multiplied by heat capacity per unit volume of the thin film 1 to find the heat conductivity from a specific expression. Consequently, the heat conductivity of the thin film which can not be present as a single layer can accurately be measured.

Platinum Based Material for Additive Technology of Gas Sensors

Abstract: We prepared platinum nanoparticle ink usable for the fabrication of MEMS microheatersof high-temperature gas sensors and thermoresistors operating up to 450 °C and present somepreliminary results on the application of the ink in sensor microheater manufacturing. The inkconsists of platinum particles (3–8 nm) suspended in ethylene glycol solution of polyvinylpyrrolidone.The ink is usable in both InkJet and AerosolJet printers. The annealing at temperature of about 600 °Cleads to the formation of uniform microheater structure. The experiments on microheater agingconfirm the stability of the printed microstructure at 450 °C for at least one year of operation. Thesubstrates used for printing were thin alumina and LTCC ceramics with thickness of 12–20 μm.

Simulation and experiment of microheater for a microfluidic polymerase chain reaction device

Abstract: In this paper, we describe the simulation and experimental results of electroplated microheater for microfluidic-base polymerase chain reaction (PCR) device. This work used finite element analysis to simulate the temperature characteristics of a PCR device. The device consists of a reaction chamber using polydimethysiloxane (PDMS) with encapsulated microhearter made of a nickel resistor wire. Design of the microheater mask layout using Tanner L-edit. Microheater can be made by low cost electroplating process. The temperature in the experiment was shown heating and cooling rates were 0.9 /spl deg/C/s and 0.8 /spl deg/C/s respectively. The thermal distribution of the device was also studied through finite elements modeling then compare to the experimental results.

A Novel Cold-Wall MOCVD Method for Fabrication of a Durable Micro-Machined SnO 2 Gas Sensor.

Abstract: A novel cold-wall metal organic chemical vapor deposition (MOCVD) method has been developed to fabricate a durable micro-machined SnO 2 thin-film gas sensor. Instead of using a hot plate or a heater around a reactor, a microheater fabricated using micromachining technology is put into the reactor and used as the heat source for thermal decomposition of the metal organic source. Since SnO 2 film is selectively deposited on the microheater using this method, no patterning process for the SnO 2 film is necessary. Moreover, the durability of the sensor fabricated using this method (N-sensor) is considerably improved compared with that of a sensor fabricated by a conventional hot-wall MOCVD method (C-sensor). The N-sensor outlasted over seven million heat cycles (500°C for 100 ms and room temperature for 100 ms), while the C-sensors were broken after a few hundred thousand heat cycles. Although the N-sensor demonstrated excellent durability, its sensitivity for methane gas was low. However, the sensitivity of the method may be improved by optimizing the deposition conditions.