SPATIALLY UNIFORM LEAD PEROVSKITE THIN-FILMS FORMED BY MOCVD

To deposit PZT (Pb(Zr,Ti)O-3) thin films on Pt films sputtered on ther mally oxidized silicon wafers, we used Pb(thd)(2), Zr(thd)(4), and Ti( i-OC3H7)(4) as metal-organic chemical vapor deposition sources. The go od composition control resulting form the use of Zr(thd)(4) provided i n-depth uniformity near the interface between Pt and deposited PZT. Th is uniformity was revealed by TEM observations and in-depth compositio n analysis using EDX with subnanometer probing radius. PZT films 80 nm thick had a leakage current of 2 x 10(-7) A/cm(2) when the applied vo ltage was 1.5 V, and equivalent to a SiO2 thickness of 0.4 nm. The var iation of composition and thickness over a 4'' wafer was about 1%. Thi s surface uniformity achieved by optimizing the source supply and pump ing system, results in the electrical uniform PZT thin films required for fabricating large-scale memory devices.