Peter S. Kirlin

Single liquid source plasma‐enhanced metalorganic chemical vapor deposition of high‐quality YBa2Cu3O7−x thin films

High‐quality YBa2Cu3O7−x films were grown in situ on LaAlO3 (100) by a novel single liquid source plasma‐enhanced metalorganic chemical vapor deposition (CVD) process. The metalorganic complexes M (thd)n, (thd=2,2,6,6‐tetramethyl‐3‐5‐heptanedionate; M=Y, Ba, Cu) were dissolved in an organic solution and injected into a vaporizer immediately upstream of the reactor inlet. The single liquid source technique dramatically simplifies current CVD processing and can significantly improve the process reproducibility. X‐ray diffraction measurements indicated that single phase, highly c‐axis oriented YBa2Cu3O7−x was formed in situ at a substrate temperature 680 °C. The as‐deposited films exhibited a mirrorlike surface, had transition temperature Tc0≂89 K, ΔTc<1 K, and Jc (77 K)=106 A/cm2.

Metalorganic Chemical Vapor Deposition of Complex Metal Oxide Thin Films by Liquid Source Chemical Vapor Deposition

The implementation of ferroelectric thin films in advanced semiconductor devices is near ; facile integration at ULSI geometries requires chemical vapor deposition (CVD) process technology. The low volatility and thermal stability of many of the existing source reagents has driven the development of liquid source CVD, in which composition is set by volumetric metering of liquids followed by flash vaporization. The methodology as well as early results for Ba 1-x Sr x TiO 3 , Pb 1-x (La x Zr 1-y Ti y ) 1-z/4 O 3 and SrBi 2 Ta 2 O 9 thin films, which are among the best reported for any deposition method, will be reviewed. These results establish liquid source CVD as a leading candidate to become the predominant deposition technology enabling the integration of ferroelectric thin films in ULSI devices.

MOCVD of BaSrTiO3 for ulsi drams

Abstract The CVD of high permittivity materials such as BaSrTiO3 presents new challenges to the semiconductor equipment and materials industries. The electrical properties of the material are a strong function of composition, microstructure and dopant concentration (electronic and ionic). However, the source reagents are typically low vapor pressure liquids, solids or solids dissolved in liquids which are challenging to manufacture with ultra-high purity and difficult to deliver with high accuracy and precision. Reactor walls must be heated to avoid condensation of the source materials and deposition temperatures are high where radiative heat transfer becomes significant. Reaction products are difficult to remove by standard dry chemical etching techniques because the halides of many of the metals are involatile inorganic salts. Design strategies to overcome these challenges and the resulting properties of BaSrTiO3 films will be discussed.

Plasma‐enhanced metalorganic chemical vapor deposition of BaTiO3 films

BaTiO3 films have been grown by plasma‐enhanced metalorganic chemical vapor deposition (PE‐MOCVD) for the first time. The BaTiO3 films were grown on Pt‐coated Si substrates in an inverted vertical reactor with a remote O2 plasma at 450 mTorr. Plasma powers exceeding 10 W reduced or eliminated the presence of CO3 in the as‐grown films at 525 and 600 °C, respectively. Films deposited at 600 °C by PE‐MOCVD were polycrystalline BaTiO3 with perovskite structure and partial texture in the [100] direction; films grown at 525 °C were amorphous. The polycrystalline BaTiO3 films had dielectric constants as large as 300, loss tangents of 0.02, and resistivities exceeding 109 Ω cm at room temperature.

Metalorganic chemical vapor deposition of Tl2Ba2CaCu2Ox superconducting thin films using fluorinated β‐diketonate source reagents

Superconducting Tl2Ba2CaCu2Ox films were fabricated using a three‐step process. Amorphous BaCaCuOF films were deposited on MgO(100) single‐crystal substrates by metalorganic chemical vapor deposition at 500 °C using fluorinated β‐diketonate complexes of Ba, Ca, and Cu. The fluorine was stripped in wet oxygen at 785 °C and c‐axis oriented Tl2Ba2CaCu2Ox films were then formed by annealing in dry at 870 °C in the presence of Tl2O3/Ba2Ca2CuN3Ox pellets. The best films showed onsets of superconductivity at 125 K and zero resistivity was achieved by 108 K. Critical current densities as high as 104 A/cm2 were obtained at 90 K.

Reduced Pressure MOCVD of C-Axis Oriented BiSrCaCuO Thin Films

BiSrCaCuO thin films were deposited on MgO(100) single crystal substrates by metalorganic chemical vapor deposition at 500°C and 2 Torr using fluorinated β-diketonate complexes of Sr, Ca and Cu and triphenylbismuth. An inverted vertical reaction chamber allowed uniform film growth over large areas (7.7 cm diameter). The as-deposited films were amorphous mixtures of oxides and fluorides and a two step annealing protocol (750°C+850−870°C) was developed which gives c-axis oriented films of Bi 2 Sr 2 Ca 1 Cu 2 O x . The post-annealed films showed onsets in the resistive transition of 110 K and zero resistivity was achieved by 83 K. Critical current densities as high as 1.1×10 4 A/cm 2 were obtained at 25 K

MOCVD growth of BaTiO/sub 3/ in an 8" single-wafer CVD reactor

A reduced-pressure MOCVD (metal-organic chemical vapor deposition) process for the growth of BaSrTiO/sub 3/ thin films was developed in a 2-in inverted-vertical reactor was developed, and preliminary studies were carried out to scale this process to a commercially available single-wafer tool. Novel process technology was used as the CVD sources were dissolved in a liquid which was measured into a vaporizer with a high-precision pump. Implementation of this process gave uniform deposition of perovskite-phase BaTiO/sub 3/ over the entire surface of a 150-mm Pt-metallized Si wafer. These films exhibited crystallographic texture in the

MOCVD of TlBaCaCuO superconducting thin films: structure-property-processing relationships

Superconducting TlBaCaCuO films were fabricated using a three step process. Amorphous BaCaCuOF films were grown on MgO(100) single crystal substrates by metalorganic chemical vapor deposition at 500 C and 4 torr using fluorinated BETA-diketonate complexes of Ba, Ca, and Cu. The fluorine was stripped in wet O2 at 785 C and c-axis oriented Tl2Ba2CaCu2x films were formed by annealing in dry O2 between 850 and 900 C in the presence of TlxOy vapor. The best films showed onsets of superconductivity at 125 K and zero resistivity was achieved by 109 K. Surface resistivities an order of magnitude lower than gold at 17 GHz (77 K) and J sub c s as high as 1000 A/cm sq (90 K) were obtained with unpatterned films.

In-Situ Growth of C-Axis Oriented YBa 2 Cu 3 O 7−x on Silicon with Composite Buffer Layers by Plasma Enhanced Metalorganic Chemical Vapor Deposition

YBa 2 Cu 3 O 7−x thin films have been grown in-situ on Si (100) with a composite buffer layer of Pt/Ta/ONO (ONO stands for a S1O 2 / Si 3 N 4 /SiO 2 trilayer) by plasma enhanced metal organic chemical vapor deposition (PE-MOCVD). X-ray diffraction measurements indicate that c-axis oriented YBa 2 Cu 3 O 7−x films are formed in-situ at substrate temperatures as low as 650 °C on Pt/Ta/ONO/Si. The composite P/Ta/ONO provided an adherent metallic interlayer and effectively prevented the interaction between YBa 2 Cu 3 O 7−x and Si. Four probe resistivity measurements indicate the onset of superconductivity at 92 K and achieved zero resistance at 65 K.

High quality Tl2Ba2CaCu2Ox thin films prepared by MOCVD

Abstract A three-step MOCVD/annealing process has been refined to reproducibly grow high quality Tl 2 Ba 2 CaCu 2 O x thin films on 25 mm × 25 mm LaAlO 3 single crystals and 25 mm diameter silver alloy discs (Consil-995). Films on LaAlO 3 were highly c-axis oriented and showed sharp resistive and inductive transitions above 100 K. The 35 GHz surface resistance of a film on Ag alloy reached 19.6 mω at 88 K.