Failure analysis of micro-heating elements suspended on thin membranes

Briand, D.; Beaudoin, Félix; Courbat, J.; Rooij, N. F. de; Desplats, Romain; Perdu, Philippe

doi:10.1016/j.microrel.2005.07.106

Cited by 26 publications

(14 citation statements)

References 6 publications

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“…The Pt/Ta heaters most likely fail due to electro-stress migration of the Pt atoms, which has been observed many times for similar structures and temperatures [1,4,[42][43][44]. Optical and SEM images also point to this cause, although more information could be obtained from cross-sections and an elemental analysis.…”

Section: Discussionmentioning

confidence: 95%

Microhotplates with TiN heaters

Creemer

Briand

Zandbergen

et al. 2008

Sensors and Actuators A: Physical

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a b s t r a c tTitanium nitride (TiN) has been investigated as a heater material for microhotplates and microreactors. TiN is available in many CMOS processes, unlike many other microheater materials. In addition, TiN has a very high melting point (2950 • C) meaning that it is stable up to higher temperatures than platinum (Pt) and polysilicon. For the first time, TiN is tested inside a conventional membrane of LPCVD silicon nitride (SiN). Two types of sputtered TiN are considered: high stress and low stress. Their performance is compared with that of e-beam evaporated Pt. The maximum average temperature of TiN heaters is 11% higher than those of Pt, and reaches over 700 • C. Failure of the TiN heaters is due to rupture of the membrane. Failure of the Pt heater is due to electro-stress migration. For high-stress TiN, the temperature coefficient of resistance is almost constant and close to that of Pt, making the material very suitable for temperature sensing. In the case of low-stress TiN the temperature coefficient of resistance (TCR) becomes nonlinear and changes sign. The large differences between the materials are explained by the grain structure. The different grain structures are related to the sputtering parameters according to the Thornton model.

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Section: Discussionmentioning

confidence: 95%

Microhotplates with TiN heaters

Creemer

Briand

Zandbergen

et al. 2008

Sensors and Actuators A: Physical

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“…The width of the platinum line becomes wider in the center of the micro-hotplate to decrease the current density and thus the temperature. This aims at having a more uniform temperature over the whole heated area of the device, which is of important in the field of gas sensing for instance [10].…”

Section: Design and Fabricationmentioning

confidence: 99%

“…Electro-stress migration was the main failure mechanism of these micro-hotplates [8,10]. The last type of heater, IrPtTa, was designed to delay this effect by adding impurities at the platinum grain boundaries.…”

Section: Design and Fabricationmentioning

confidence: 99%

“…Simulations models and accelerated aging test protocols were developed to investigate the failure mechanisms in order to optimize the reliability of the devices [6][7][8][9][10]. The investigations have shown that platinum-based micro-heaters are more robust than those made of polysilicon when devices * Corresponding author.…”

Section: Introductionmentioning

confidence: 99%

“…The use of Ta as adhesion layer has the advantage over Ti to be compatible with the deposition of LPCVD Si 3 N 4 , providing hotplates with more robust membranes, and to diffuse less in platinum. The influence of the temperature during the processing or post-processing on the microstructural, electrical and mechanical properties of Pt-Ta-based metallizations has already been presented [15,17,18], as well as the degradation of Pt-Ta-based micro-heater operating at high temperatures [7,8,10,18].…”

Section: Introductionmentioning

confidence: 99%

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Reliability improvement of suspended platinum-based micro-heating elements

Courbat

Briand

Rooij

2008

Sensors and Actuators A: Physical

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Micro-hotplates consisting of a platinum-based heating element embedded in two low-stress silicon nitride layers were fabricated. In this communication, we report on the composition of the heater and its influence on both the micro-hotplate's life expectancy and the highest reachable operating power. These factors were characterized by measuring the deformation of the membrane, by ramping up the power until breakdown and by performing accelerated aging tests. Finally, the failure mechanisms were investigated using optical and SEM observations. The type of material used as adhesion layer has a strong influence on the heating element's performances. Addition of iridium significantly improved the lifetime of the device.

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