Piezoelectric materials are widely used for microscale sensors and actuators but can pose material compatibility challenges. This paper reports a post-CMOS compatible fabrication process for piezoelectric sensors and actuators on silicon using only standard CMOS metals. The piezoelectric properties of aluminum nitride (AlN) deposited on titanium (Ti) by reactive sputtering are characterized and microcantilever actuators are demonstrated. The film texture of the polycrystalline Ti and AlN films is improved by removing the native oxide from the silicon substrate in situ and sequentially depositing the films under vacuum to provide a uniform growth surface. The piezoelectric properties for several AlN film thicknesses are measured using laser doppler vibrometry on unpatterned wafers and released cantilever beams. The film structure and properties are shown to vary with thickness, with values of d 33f , d 31 and d 33 of up to 2.9, −1.9 and 6.5 pm V −1 , respectively. These values are comparable with AlN deposited on a Pt metal electrode, but with the benefit of a fabrication process that uses only standard CMOS metals.

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Pre-Silicide clean is a critical step in NiSi integration to keep silicide/Si interface clean and defect-free for good device performance. Traditional pre-silicide clean uses HF wet clean which requires tight queue time control to prevent native oxide growth before Ni deposition. We present in this paper an in situ dry chemical clean technology and its impact on NiSi and Ni(Pt)Si Integration, compared with traditional HF wet clean. The new in situ dry pre-silicide clean selectively etches away oxide, and prepare the surface for subsequent Ni PVD deposition without leaving its vacuum environment. The electrical results show lower silicide resistance, tighter resistance distribution, and better diode characteristics with in situ dry clean than with HF clean.