UV Laser Ablation of PLZT and PSZT Films
- PDF / 738,156 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 58 Downloads / 184 Views
1075-J07-16
UV Laser Ablation of PLZT and PSZT Films Patrick W Leech1, Anthony S Holland2, Sharath Sriram2, and Madhu Bhaskaran2 1 CSIRO, CMSE, Clayton, Victoria, 3168, Australia 2 School of Electrical and Computer Engineering, RMIT University, Melbourne, 3001, Australia ABSTRACT The ablation of strontium-doped lead zirconate titanate (PSZT) and lanthanum-doped lead zirconate titanate (PLZT) films has been examined using a 5 ns pulsed excimer laser. Individual squares were patterned with sides in the range of 10-30 µm using single and multiple pulses. The depth of ablation in PLZT films was higher at all fluences than in PSZT films. The morphology of the etched surfaces has comprised the formation of globules which had diameters of 200-250 nm in PLZT and 1400-1600 nm in PSZT films. The diameter of the globules has been shown to increase with fluence until reaching an approximately constant size at >20 J/cm2 in both types of film. The composition of the films following ablation has been analyzed using x-ray photoelectron spectroscopy (XPS) and energy dispersive x-ray (EDX) spectroscopy.
INTRODUCTION The direct patterning of thin films by excimer laser has been reported in various ceramic substrates including partially stabalized zirconia [1] and NdBa2Ca3O [2]. The short pulse widths (ns) of the laser and the highly localized heat zone have enabled precise control of the ablation process through the beam parameters. This technique of direct patterning is comparable with the multi-step processes using reactive ion etching (RIE) and ion beam etching (IBE). The micromachining of the important ferroelectric material, lead zirconate titanate (PZT) by excimer laser was initially reported by Eyett [3] and further demonstrated by Zeng [4] and Desbiens [5]. Although these studies were performed in bulk PZT, the excimer laser also offers potential for the patterning of PZT-based films. PZT has become a promising material in the fabrication of electromechanical devices such as bio-sensing cantilevers and sensors/ actuators. In these applications, the exceptional piezoelectric properties of PZT have been coupled with structural properties of silicon. Strontium (Sr) doping has been shown to strongly enhance the piezoelectric properties of PZT [6, 7]. Furthermore, the growth of PSZT films with the perovskite orientation, the optimum orientation for piezoelectric properties, has recently been demonstrated using magnetron sputter deposition on platinised silicon substrates [8]. A similar sputter technique has also been used to produce films of lanthanum doped PZT in the perovskite phase [9]. PLZT in a perovskite orientation has been characterized by a high electro-optic coefficient with potential for application in a range of optoelectronic and optical devices. In this paper, we examine for the first time, the patterning of Sr- and La-doped PZT films by excimer laser. These films contained a dopant concentration of either Sr or La in PZT within a perovskite structure. The characteristics of ablation of the films have been examined
Data Loading...
