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A low-temperature (< 300 • C) low-stress microelectromechanical systems fabrication process based on a silicon carbide structural layer is presented. A partially conductive sintered target enables low-temperature dc sputtering of amorphous silicon carbide (SiC) at high deposition rates (75 nm/min). The low stress of the structural film allows for mechanically reliable structures to be fabricated, while the low-temperature deposition allows for pre-SiC metallization. The process is designed for low-cost film deposition and for complementary metal-oxide-semiconductor postintegration, stemming from chemical and thermal compatibility. Process flow, deposition, etching, and stress control are discussed, and a detailed process characterization is reported.[ 2010-0235]Index Terms-Complementary metal-oxide-semiconductor (CMOS) compatible, direct current (dc) sputtering, low temperature, microelectromechanical systems (MEMS), silicon carbide (SiC), stress control, surface micromachining.

Microelectromechanical beam resonators and arrays are fabricated using a custom low-temperature complementarymetal-oxide-semiconductor-compatible silicon carbide microfabrication process, detailed in Part I of this paper. Theoretical aspects are presented with modal analysis and numerical methods. Measurements of the resonant frequency, the quality factor, the transmission, and the tuning characteristics are presented for different device types and dimensions. Trends are analyzed, and performance metrics dependences are investigated. A tuning method based on integrated heaters is introduced and tested, yielding a very desirable constant insertion-loss tuning and a wide tuning range. Quality factors of up to 1493 and resonant frequencies of up to 26.2 MHz are demonstrated. Both the Young's modulus and the residual stress of the SiC film are extracted (261 GPa and < ±30 MPa, respectively), and favorably compare to values reported for polysilicon. [2010-0235] Index Terms-Micromechanical resonators, microelectromechanical systems (MEMS), resonator arrays, silicon carbide (SiC), surface micromachining, thermal tuning.

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