Sputter-deposited PZT-on-Silicon Optimization for C-band Electro-Optic Modulation

Ferroelectric materials exhibit interesting electric, mechanical and optical properties. Particularly,tin-film lead zirconium titanate (PZT) has been used as a standard piezo-electric material in micro-electro-mechanical systems. Interestingly, it has one of the highest electro-optic properties that can be exploited to make high-speed on-chip light modulators. In this work, we demonstrate sputter-deposited PZT on silicon-on-insulator wafers. Desired phase and film morphology is achieved through process and buffer layer engineering. We present results on buffer layer screening between MgO, TiO2 and Pt. MgO is identified as a suitable buffer layer from an optical and film growth perspective. We achieve a measured coercive field for PZT/MgO and PZT/Pt film is 50 kV/cm and 30 kV/cm, respectively. We use a PZT-loaded ring modulator with an electro-optic response of 14 pm/V.