SiGe MEMS at processing temperatures below 250 °C

El-Rifai, Joumana; Sedky, Sherif; Hoof, R. Van; Severi, S.; Lin, Dennis; Sangameswaran, Sandeep; Puers, Robert; Hoof, Chris Van; Witvrouw, Ann

doi:10.1016/j.sna.2012.01.035

Cited by 5 publications

(3 citation statements)

References 14 publications

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“…SiGe-based MEMS have generated considerable interest because the processing temperature can be limited to below 450°C, 8 enabling direct integration with CMOS and even polymer substrates in some cases. 37 CMOS-MEMS integration has many important advantages including noise reduction, improved precision, and even new device applications; however, these are limited typically to the operational temperatures of CMOS of ,150°C. Conversely, silicon carbide (SiC) and polymer-derived silicon carbonitride (Si-C-N) ceramics are two of the most promising Si-based material systems with the potential for elevated temperature operation.…”

Section: Other Si-based Materials Systemsmentioning

confidence: 99%

Emerging materials for microelectromechanical systems at elevated temperatures

2014

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Extension of microelectromechanical systems (MEMS) into more extreme operating conditions will require a wider range of material properties than are currently available in conventional systems. Successful integration of new materials is dependent on concurrent development of compatible fabrication routes and scale appropriate evaluation techniques. This review focuses on emerging material classes that have potential to replace silicon-based MEMS in elevated temperature applications. Basic silicon mechanical properties and micromachining methods are reviewed to provide context for developing material systems such as silicon carbide, silicon carbonitrides, and several nickel-based alloys. Potential improvements in strength, thermal stability, and reliability are juxtaposed with fabrication, reproducibility, and economic feasibility issues that must also be addressed.

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Section: Other Si-based Materials Systemsmentioning

confidence: 99%

Emerging materials for microelectromechanical systems at elevated temperatures

2014

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“…In addition, it requires the limitation of the process to a maximum processing temperature (thermal budget) of 400 °C to avoid the destruction of the lower layers in the CMOS substrate (e.g., interconnects). An additional reduction in the thermal budget beyond the CMOS compatibility limits, i.e., below 250 °C, is needed for integration on top of flexible substrates [ 8 ]. Despite the many favored characteristics of surface micromachining for high volume MEMS applications, bulk micromachining has been well-suited in devices requiring large vibrating masses such as inertial sensors [ 3 ].…”

Section: Introductionmentioning

confidence: 99%

“…Despite the many favored characteristics of surface micromachining for high volume MEMS applications, bulk micromachining has been well-suited in devices requiring large vibrating masses such as inertial sensors [ 3 ]. Furthermore, forming high-quality mechanical layers at a low temperature in surface micromachining often requires non-traditional procedures such as laser treatment [ 8 ]. Silicon carbide (SiC), in addition to having been introduced as a CMOS compatible material [ 9 , 10 , 11 ], features excellent mechanical properties such as higher elastic modulus and yield strength values relative to silicon that makes it an attractive choice for MEMS applications.…”

Section: Introductionmentioning

confidence: 99%

Hard-Baked Photoresist as a Sacrificial Layer for Sub-180 °C Surface Micromachining Processes

Tawfik

Elsayed²,

Nabki

et al. 2018

Micromachines

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This letter proposes a method for utilizing a positive photoresist, Shipley 1805, as a sacrificial layer for sub-180 °C fabrication process flows. In the proposed process, the sacrificial layer is etched at the end to release the structures using a relatively fast wet-etching technique employing resist remover and a critical point dryer (CPD). This technique allows high etching selectivity over a large number of materials, including silicon-based structural materials such as silicon-carbide, metals such as titanium and aluminum, and cured polymers. This selectivity, as well as the low processing thermal budget, introduces more flexibility in material selection for monolithic integration above complementary metal oxide semiconductor (CMOS) as well as flexible substrates.

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