The Role of Phase Changes in TiO2/Pt/TiO2 Filaments

Bíró, Ferenc; Hajnal, Z.; Dücső, Csaba; Bársony, I.

doi:10.1007/s11664-018-6066-3

Cited by 4 publications

(2 citation statements)

References 22 publications

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“…The Pt filaments are completely sandwiched between TiO 2 /SiO 2 layers, thereby the encapsulated Pt is not directly exposed to air during testing. The applied 25 nm thick TiO 2 layers at both sides of the 350 nm thick Pt filament are used to enhance adhesion to the SiO 2 layers and also to prevent the formation of platinum-titan intermetallic phase during the high temperature operation, i.e., it improves the structural stability and the temperature-resistance characteristics of the Pt heater [26]. KOH etching from the back side of the substrate was used for the membrane release.…”

Section: Silicon Mems Microhotplate Platformmentioning

confidence: 99%

Silicon MEMS Thermocatalytic Gas Sensor in Miniature Surface Mounted Device Form

et al. 2021

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A reduced size thermocatalytic gas sensor was developed for the detection of methane over the 20% of the explosive concentration. The sensor chip is formed from two membranes with a 150 µm diameter heated area in their centers and covered with highly dispersed nano-sized catalyst and inert reference, respectively. The power dissipation of the chip is well below 70 mW at the 530 °C maximum operation temperature. The chip is mounted in a novel surface mounted metal-ceramic sensor package in the form-factor of SOT-89. The sensitivity of the device is 10 mV/v%, whereas the response and recovery times without the additional carbon filter over the chip are <500 ms and <2 s, respectively. The tests have shown the reliability of the new design concerning the hotplate stability and massive encapsulation, but the high degradation rate of the catalyst coupled with its modest chemical power limits the use of the sensor only in pulsed mode of operation. The optimized pulsed mode reduces the average power consumption below 2 mW.

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Section: Silicon Mems Microhotplate Platformmentioning

confidence: 99%

Silicon MEMS Thermocatalytic Gas Sensor in Miniature Surface Mounted Device Form

et al. 2021

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“…Several approaches have been proposed for the mitigation of delamination and recrystallization of noble metal thin films at high temperatures: (1) the deposition of bilayer structures with an adhesion layer (Ti, Ta, Cr, Zr) between the substrate and the conductive layer [17][18][19][20][21][22][23][24] or the use of an oxidizing atmosphere during the initial stage of the noble metal sputtering [25,26], (2) the sputtering of a protective dielectric layer (Si, Al 2 O 3 , Si 3 N 4 , TiO 2 , SiAlON, SiO 2 + Si 3 N 4 ) onto the top surface of metal layer [16,24,[27][28][29][30], (3) alloying platinum with metals that have higher melting point (Ir, Rh) [24,[31][32][33][34], and (4) the incorporation of refractory oxides (ZrO 2 , HfO 2 , Nb 2 O 3 , Y 2 O 3 , RuO 2 ), acting as anchors to stabilize the grain boundaries of the metal phase [24,33,[35][36][37][38]. All these approaches require recrystallization annealing at temperatures exceeding the operating temperature range of thin-film devices [17,39].…”

Section: Introductionmentioning

confidence: 99%

Towards High-Temperature MEMS: Two-Step Annealing Suppressed Recrystallization in Thin Multilayer Pt-Rh/Zr Films

Pleshakov,

Kalinin,

Ivanov

et al. 2023

Micromachines

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Platinum-based thin films are widely used to create microelectronic devices operating at temperatures above 500 °C. One of the most effective ways to increase the high-temperature stability of platinum-based films involves incorporating refractory metal oxides (e.g., ZrO2, HfO2). In such structures, refractory oxide is located along the metal grain boundaries and hinders the mobility of Pt atoms. However, the effect of annealing conditions on the morphology and functional properties of such multiphase systems is rarely studied. Here, we show that the two-step annealing of 250-nm-thick Pt-Rh/Zr multilayer films instead of the widely used isothermal annealing leads to a more uniform film morphology without voids and hillocks. The composition and morphology of as-deposited and annealed films were investigated using X-ray diffraction and scanning electron microscopy, combined with energy-dispersive X-ray spectroscopy. At the first annealing step at 450 °C, zirconium oxidation was observed. The second high-temperature annealing at 800–1000 °C resulted in the recrystallization of the Pt-Rh alloy. In comparison to the one-step annealing of Pt-Rh and Pt-Rh/Zr films, after two-step annealing, the metal phase in the Pt-Rh/Zr films has a smaller grain size and a less pronounced texture in the <111> direction, manifesting enhanced high-temperature stability. After two-step annealing at 450/900 °C, the Pt-Rh/Zr thin film possessed a grain size of 60 ± 27 nm and a resistivity of 17 × 10−6 Ω·m. The proposed annealing protocol can be used to create thin-film MEMS devices for operation at elevated temperatures, e.g., microheater-based gas sensors.

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Microhotplates based on Pt and Pt-Rh films: The impact of composition, structure, and thermal treatment on functional properties

Калинин

Roslyakov

Tsymbarenko

et al. 2021

Sensors and Actuators A: Physical

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The Role of Phase Changes in TiO2/Pt/TiO2 Filaments

Cited by 4 publications

References 22 publications

Silicon MEMS Thermocatalytic Gas Sensor in Miniature Surface Mounted Device Form

Silicon MEMS Thermocatalytic Gas Sensor in Miniature Surface Mounted Device Form

Towards High-Temperature MEMS: Two-Step Annealing Suppressed Recrystallization in Thin Multilayer Pt-Rh/Zr Films

Microhotplates based on Pt and Pt-Rh films: The impact of composition, structure, and thermal treatment on functional properties

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