Low-Temperature Deposition of Pb(Zr,Ti)O₃ Thin Films on Si Substrates Using Ba(Mg_1/3Ta_2/3)O₃ as Buffer Layer

Utilization of Ba(Mg_1/3Ta_2/3)O₃ materials as buffer layers was found to achieve perovskite Pb(Zr,Ti)O₃ (PZT) thin film growth on silicon at very low substrate temperature (∼350 °C) by in situ pulsed laser deposition (PLD). Formation of a continuous layer is of critical importance in order to use the Ba(Mg_1/3Ta_2/3)O₃ materials as diffusion barriers for suppressing the PZT-to-Si interaction and, at the same time, as seeding layers for enhancing the crystallization kinetics of the PZT films. Perovskite and amorphous PZT thin films can be obtained by simply adjusting the ambient oxygen pressure or substrate temperature in the PLD process. The amorphous PZT films possess a markedly smaller optical refractive index than the perovskite ones (n_amorphous = 2.02 and n_perovskite = 2.39), such that the perovskite/amorphous PZT films are a good combination for core/cladding materials for planar optical waveguides.