A high d33 CMOS compatible process for aluminum nitride on titanium

We present a CMOS compatible fabrication process which utilizes aluminum nitride with titanium electrodes for high-speed piezoelectric actuation. Aluminum nitride film morphology was improved by maintaining vacuum between film depositions and by the inclusion of an aluminum nitride interlayer. A rocking curve full-width at half-maximum of less than 3 degrees was achieved. Unimorph actuators were fabricated from silicon cantilevers and piezoelectric coefficients of 3.0 pm/V and 1.65 pm/V were measured for d₃₃ and d₃₁, respectively. This performance is comparable to reports for AlN processed without CMOS compatible electrode materials.