Preparation of Pb(Zr,Ti)O3 thin films by metalorganic chemical vapor deposition for low voltage ferroelectric memory

2003 ◽  
Vol 93 (3) ◽  
pp. 1713-1717 ◽  
Author(s):  
S. R. Gilbert ◽  
S. Hunter ◽  
D. Ritchey ◽  
C. Chi ◽  
D. V. Taylor ◽  
...  
2001 ◽  
Vol 16 (12) ◽  
pp. 3583-3591 ◽  
Author(s):  
Hye Ryoung Kim ◽  
Seehwa Jeong ◽  
Chung Bae Jeon ◽  
Oh Seong Kwon ◽  
Cheol Seong Hwang ◽  
...  

The metalorganic chemical vapor deposition of very thin (<50 nm) Pb(Zr,Ti)O3 (PZT) thin films was performed for high density (>32 mega bit) ferroelectric memory devices. The growth temperatures were set between 450 and 530 °C to obtain a smooth surface morphology and prevent damage to the underlying reaction barrier layer. The average grain size of a 50-nm-thick film on a Pt electrode was about 34 nm with a size distribution (σ2) of 11 nm. These values are much smaller than the sol-gel-derived PZT films (55 and 25 nm, respectively). Very thin films with a thickness of approximately 30 nm were prepared at wafer temperatures ranging from 500 to 525 °C. Even with the very small thickness, the films showed good ferroelectric properties with a typical remanent polarization from 10 to 15 μC/cm2 and an extremely low coercive voltage of 0.3 V. However, the leakage current density was rather high resulting in nonsaturating polarization versus voltage curves. Even though good ferroelectric properties were obtained, the formation of PtxPby alloys on top of the Pt electrode was consistently observed. This precludes the reliable control of film composition and electrical performance. The adoption of an Ir electrode successfully eliminated intermetallic alloy formation and resulted in better and reproducible process control. A 50-nm-thick PZT film on an Ir/IrO2/SiO2/Si substrate also showed a reasonable ferroelectric performance.


2000 ◽  
Vol 87 (10) ◽  
pp. 7430-7437 ◽  
Author(s):  
Y. Gao ◽  
C. L. Perkins ◽  
S. He ◽  
P. Alluri ◽  
T. Tran ◽  
...  

1994 ◽  
Vol 361 ◽  
Author(s):  
D.L. Kaiser ◽  
M.D. Vaudin ◽  
L.D. Rotter ◽  
Z.L. Wang ◽  
J.P. Cline ◽  
...  

ABSTRACTMetalorganic chemical vapor deposition (MOCVD) was used to deposit epitaxial BaTiO3 thin films on (100) MgO substrates at 600°C. The metalorganic precursors employed in the deposition experiments were hydrated Ba(thd)2 (thd = C11H19O2) and titanium isopropoxide. The films were analyzed by means of transmittance spectroscopy, wavelength dispersive x-ray spectrometry, secondary ion mass spectrometry depth profiling, x-ray diffraction, high resolution transmission electron microscopy, selected area electron diffraction, nanoscale energy dispersive x-ray spectrometry and second harmonic generation measurements. There was no evidence for interdiffusion between the film and substrate. The x-ray and electron diffraction studies showed that the films were oriented with the a-axis normal to the substrate surface, whereas second harmonic generation measurements showed that the films had some c-axis character.


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