Liquid Delivery MOCVD of Ferroelectric PZT

1995 ◽  
Vol 415 ◽  
Author(s):  
J. F. Roeder ◽  
B. A. Vaartstra ◽  
P. C. Van Buskirk ◽  
H. R. Beratan

ABSTRACTFerroelectric PbZrxTi1-x O3 (PZT) films have been deposited by chemical vapor deposition using flash vaporized metalorganic precursors. Crystalline perovskite films approximately 3000Å thick were deposited on Pt/Si substrates at 550–590°C and had dielectric coefficients in the range of 600–1900. Dielectric constant was found to increase with increasing Zr/Ti ratio, rising to the largest values near the morphotropic phase boundary. Remanent polarizations of the PZT were between 20–27 μC/cm2 and the coercive field decreased with increasing Zr/Ti ratio from 43 to 21 kV/cm. Pyroelectric coefficients were measured using the Byer-Roundy technique and ranged from 20–30 nC/cm2K. At 550°C, a direct relationship was observed between precursor composition and film composition. At 590°C, volatility of PbO became appreciable and composition of films with Zr/(Zr+Ti) = 0.3 remained near stoichiometry over a wide range of excess Pb in the precursor. However, this effect was found to diminish for higher ratios of Zr/Ti. The orientation of the PZT films deposited over a range of precursor compositions was similar with some [100] preferred orientation. In contrast, the orientation of a PbTiO3 films could be manipulated by the Pb/Ti ratio in the precursor, with [111] preferred orientations predominating at lower Pb/Ti and [ 100/001]–[111] mixed orientations at higher Pb/Ti ratios.

1992 ◽  
Vol 281 ◽  
Author(s):  
Rong Z. Qian ◽  
D. Kinosky ◽  
A. Mahajan ◽  
S. Thomas ◽  
J. Fretwell ◽  
...  

ABSTRACTRemote Plasma-enhanced Chemical Vapor Deposition (RPCVD) has been successfully used to grow GexSi1−x/Si (x = 0.1 – 1.0) heteroepitaxial structures at low temperatures (∼450°C). This technique utilizes a noble gas (Ar or He) r-f plasma to decompose reactant gases (SiH4 and GeH4) and drive the chemical deposition reactions in the gas phase as well as on the substrate surface. Growth of pure Ge on Si is of great interest because it provides a promising technique for making suitable low-cost substrates for thin-film Ge photodetectors as well as GaAs devices on Si substrates. The realization of these applications depends on the ability to grow high-quality epitaxial Ge layers on Si substrates. Since GaAs is lattice matched to Ge, growth of Ge layers on Si substrates with good crystalline perfection would permit the integration of GaAs and Si devices. Islanding was observed after the growth of pure Ge films directly on Si(100) for a wide range of plasma powers (7W ∼ 16W) in RPCVD. Cross-sectional TEM analysis showed that the islands have complicated facet structures, including {311} planes. Graded Gex Si1−x buffer layers with different Ge profiles have been used prior to the growth of Ge. It was found that uniform Ge films can be obtained using a buffer with an abrupt Ge profile, and the dislocation density in the Ge film decreases with increasing distance from the substrate.


2003 ◽  
Vol 766 ◽  
Author(s):  
Raymond N. Vrtis ◽  
Mark L. O'Neill ◽  
Jean L. Vincent ◽  
Aaron S. Lukas ◽  
Brian K. Peterson ◽  
...  

AbstractWe report on our work to develop a process for depositing nanoporous organosilicate (OSG) films via plasma enhanced chemical vapor deposition (PECVD). This approach entails codepositing an OSG material with a plasma polymerizable hydrocarbon, followed by thermal annealing of the material to remove the porogen, leaving an OSG matrix with nano-sized voids. The dielectric constant of the final film is controlled by varying the ratio of porogen precursor to OSG precursor in the delivery gas. Because of the need to maintain the mechanical strength of the final material, diethoxymethylsilane (DEMS) is utilized as the OSG precursor. Utilizing this route we are able to deposit films with a dielectric constant of 2.55 to 2.20 and hardness of 0.7 to 0.3 GPa, respectively.


2021 ◽  
Author(s):  
Omar D. Jumaah ◽  
Yogesh Jaluria

Abstract Chemical vapor deposition (CVD) is a widely used manufacturing process for obtaining thin films of materials like silicon, silicon carbide, graphene and gallium nitride that are employed in the fabrication of electronic and optical devices. Gallium nitride (GaN) thin films are attractive materials for manufacturing optoelectronic device applications due to their wide band gap and superb optoelectronic performance. The reliability and durability of the devices depend on the quality of the thin films. The metal-organic chemical vapor deposition (MOCVD) process is a common technique used to fabricate high-quality GaN thin films. The deposition rate and uniformity of thin films are determined by the thermal transport processes and chemical reactions occurring in the reactor, and are manipulated by controlling the operating conditions and the reactor geometrical configuration. In this study, the epitaxial growth of GaN thin films on sapphire (AL2O3) substrates is carried out in two commercial MOCVD systems. This paper focuses on the composition of the precursor and the carrier gases, since earlier studies have shown the importance of precursor composition. The results show that the flow rate of trimethylgallium (TMG), which is the main ingredient in the process, has a significant effect on the deposition rate and uniformity of the films. Also the carrier gas plays an important role in deposition rate and uniformity. Thus, the use of an appropriate mixture of hydrogen and nitrogen as the carrier gas can improve the deposition rate and quality of GaN thin films.


2012 ◽  
Vol 523 ◽  
pp. 25-28 ◽  
Author(s):  
Meng Yang ◽  
Shuichi Ogawa ◽  
Susumu Takabayashi ◽  
Taiichi Otsuji ◽  
Yuji Takakuwa

ACS Nano ◽  
2013 ◽  
Vol 8 (1) ◽  
pp. 269-274 ◽  
Author(s):  
Jin-Young Kim ◽  
Jongho Lee ◽  
Wi Hyoung Lee ◽  
Iskandar N. Kholmanov ◽  
Ji Won Suk ◽  
...  

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