Low temperature processing of PZT thin films with Excimer laser annealing

Abstract

The effect of excimer laser annealing on Pb(Zr, Ti)O3 (PZT) thin films at low substrate temperature (< 400 ℃) has been investigated in this work. The amorphous PZT thin films were prepared by a sol-gel method. The PZT precursor was prepared from lead acetate, zirconium acetylacetonate, and titanium isopropoxide. The starting materials were dissolved in n-propanol and 1,3-propanediol. The amorphous PZT thin films were laser-annealed (using KrF excimer laser) as a function of the laser energy density and the number of laser pulse. In addition, the excimer laser annealing parameters, the ambient gas, and the substrate temperature (< 400 ℃) on the crystallization of the PZT thin films were studied, as were the structural and electric behaviors. Structural properties of PZT thin films are characterized by using X-ray diffraction (XRD), and scanning electron microscopy (SEM). The electric properties were analyzed using a RT66A test system and an Agilent 4294A impedance analyzer. With irradiated-excimer laser annealing, we observe an improvement the structural and electrical properties due to the crystallization of the amorphous PZT thin films, depending on the energy density and the pulse number. These results demonstrate the potential of good-crystalline PZT thin films on temperature sensitive substrates at low temperatures. This low temperature process by excimer laser annealing could be useful in the integration of ferroelectric devices and semiconductor devices for advanced system-on-chip applications.