Preparation of Ag-alloy top-electrode for ferrolectric films.

提出了一种新型的银合金(97Ag-1Pd-2Cu，摩尔分数)作为锆钛酸铅(PZT)薄膜的顶电极。对银合金的成分进行了分析。在纯银中加入0.1%以上的Pd时，电极的绝缘电阻有所提高。对含铜0.1%~5%的纯银的电极，其耐热性、绝缘性和粘附性都得到了改善。采用化学溶液沉积法(CSD法)在Pt/Ti/SiO_2/Si衬底上制备了PZT铁电薄膜。用溅射方法在该PZT薄膜上制备了直径为0.5 mm的铂和银合金顶电极。得到的薄膜在氧气和氢气气氛(N_2-4%H_2)中进行热处理，得到了如下认识：(1)氧气气氛铂和银合金电极都能在500℃以下保持良好的铁电性。(2)氢气气氛在铂上电极的情况下，经过3CO℃以上的退火后，铁电性消失。在300℃以上退火后，铂的底电极从衬底上剥落，而对于银合金上电极，400℃退火后，银合金电极与PZT膜之间没有发生化学反应。用该银合金电极在350℃的温度下仍能保持铁电性，可望作为铁电材料的新型电极材料。

An Ag-alloy (97Ag-1Pd-2Cu in mol%) was proposed as a new top-electrode for lead zirconate titanate (PZT) films.1. The composition of the Ag-alloy was examined. The insulation resistance of the electrode has improved to the electrode of the composition which adds Pd of 0.1% or more to the pure silver. A heat-resistant, the insulation resistance, and adhesion characteristic have improved to the electrode of the composition which does Cu from 0.1 to 5% to the virgin silver.2. PZT ferroelectric thin film was prepared on the Pt/Ti/SiO_2/Si substrate by chemical solution deposition method (CSD method). Pt and the Ag-alloy top-electrode of 0.5mm in the diameter were made on this PZT thin film by the sputtering method. The obtained film was heat-treated by the oxygen and hydrogen atmosphere (N_2-4%H_2), and the following knowledge was obtained.(1) Oxygen atmosphereIt has been understood for both Pt and the Ag-alloy electrode to be able to maintain excellent ferroelectricity up to 500℃.(2) Hydrogen atmosphereIn the case of Pt top-electrode, the ferroelectricity of PZT films disappeared after annealing over 3CO℃. Exfoliations of Pt bottom-electrode from substrate were observed after annealing over 300℃.In the case of the Ag-alloy top-electrode, no chemical reaction between the Ag-alloy electrode and PZT film was observed after annealing at 400℃. The ferroelectricity of PZT film was maintain ed even after annealing at 350℃ using the Ag-alloy electrode.It is guessed that the Ag alloy electrode developed by this research can be used as new electrode for ferroelectric materials.