Pulsed laser deposition of piezoelectric lead zirconate titanate thin films maintaining a post-CMOS compatible thermal budget.

Integration of lead zirconate titanate (Pb[Zrx,Ti1-x]O3 – PZT) thin films on complementary metal-oxide semiconductor substrates (CMOS) is difficult due to the usually high crystallization temperature of the piezoelectric perovskite PZT phase, which harms the CMOS circuits. In this work, a wafer-scale pulsed laser deposition tool was used to grow 1 μm thick PZT thin films on 150mm diameter silicon wafers. Three different routes towards a post-CMOS compatible deposition process were investigated, maintaining a post-CMOS compatible thermal budget limit of 445°C for 1 h (or 420°C for 6 h). By crystallizing the perovskite LaNiO3 seed layer at 445°C, the PZT deposition temperature can be lowered to below 400°C, yielding a transverse piezoelectric coefficient e31,f of -9.3 C/m2. With the same procedure, applying a slightly higher PZT deposition temperature of 420°C, an e31,f of -10.3 C/m2 can be reached. The low leakage current density of below 3×10-6A/cm2 at 200 kV/cm allows for application of the post-CMOS compatible PZT thin films in low power micro-electro-mechanical-systems actuators. [ABSTRACT FROM AUTHOR]