Characterization of Pb[sub x]Pt[sub y] Alloy Formation on a Pt Substrate during Liquid-Delivery MOCVD of Pb(Zr,Ti)O[sub 3] Thin Films

Abstract

Pb x Pt y alloy formation and its influence on Pb͑Zr,Ti͒O 3 ͑PZT͒ film growth during liquid-delivery metallorganic chemical vapor deposition ͑MOCVD͒ of ferroelectric PZT thin films on Pt electrodes are investigated. When an excessive amount of Pb precursor and a deficient amount of oxygen are supplied during MOCVD at temperatures near 550°C, Pb diffuses along the grain boundaries into the Pt substrate, causing the formation of an alloy layer. Compared to a thicker Pt electrode ͑150 nm͒, a thinner Pt substrate ͑50 nm͒ enhances the alloy layer formation due to the higher diffusion of Pb along the more abundant Pt grain boundaries. The alloy layer enhances the Pb incorporation into the PZT film and improves the crystallization of the PZT layer on top due to better structural compatibility between PZT and the alloy. When the deposition temperature is 570°C the alloy formation is initiated in the early stage of the film deposition but undergoes thermal decomposition in the later stage ͑Ͼ ϳ 15 min͒. Therefore, a constant Pb concentration is obtained after the initial decrease for a deposition period Ͻ15 min.

The Effects of Oxidants on the Growth Behavior of PbTiO3 Thin Film by Atomic Layer Deposition

“…Pt and Ir were usually used as the electrode of the ferroelectric capacitor. However, Pt electrode formed Pb x Pt y alloy at the interface with the PTO (or PZT) film (13). Ir electrode is suitable for the ALD and MOCVD processes of the ferroelectric thin films but the CVD and ALD processes for Ir electrode have not been developed to the level which is sufficient for its application to the semiconductor device fabrication.…”

Characteristics of Polycrystalline SrRuO[sub 3] Thin-Film Bottom Electrodes for Metallorganic Chemical-Vapor-Deposited Pb(Zr[sub 0.2]Ti[sub 0.8])O[sub 3] Thin Films

“…This was reported in detail in a separate paper. 22 The variation in the Zr ratio depending on the types of electrodes should be noted ͑Fig. 7b͒.…”

Fabrication of Ferroelectric Pb(Zr,Ti)O3 Thin Films by Spray Metalorganic Chemical Vapor Deposition

“…Liquid delivery metalorganic chemical vapor deposition (LD-MOCVD) has been researched and developed as a fabrication technique for ferroelectric thin films. [1][2][3][4][5][6][7][8][9][10][11] However, notwithstanding its capacity for high-quality thin film formation, the LD-MOCVD system is highly complex and requires continuous maintenance for stable operation. The most important subjects to be developed related to LD-MOCVD techniques are the vaporization system of liquid sources and the transport of vaporized source gases.…”