Atomic layer deposition metals

Several patents dealing with the use of volatile metal amidinate complexes in MOCVD or ALD processes have appeared in the literature.The use of volatile amidinato complexes of Al, Ga, and In in the chemical vapor deposition of the respective nitrides has been reported. For example, [PhC(NPh)2]2GaMe was prepared in 68% yield from GaMes and N,N -diphenylbenzamidine in toluene. Various samples of this and related complexes could be heated to 600 °C in N2 to give GaN. A series of homoleptic metal amidinates of the general type [MIRCfNROilnl (R = Me, Bu R = Pr, BuO has been prepared for the transition metals Ti, V, Mn, Fe, Co, Ni, Cu, Ag, and La. The types of products are summarized in Scheme 226. The new compounds were found to have properties well-suited for use as precursors for atomic layer deposition (ALD) of thin films. 

Reductive UPD is the major atomic layer deposition processes used in EC-ALE, Equation 1. Many metals can be obtained in a soluble oxidized form, from which atomic layers can be deposited at underpotentials. Control points are the reactant... 

Wang, X., S.M. Tabakman, and H. Dai, Atomic layer deposition of metal oxides on pristine and functionalized graphene. Journal of the American Chemical Society, 2008.130(26) p. 8152-8153. 

Keywords Atomic layer deposition Thin films Metal alkyl precursors ... 

During the 25-year history of atomic layer deposition several volatile compounds of different chemical nature have been studied for deposition processes. Typically these volatile compounds have been either metals, halides, nitrates or inorganic chelates and, more recently and still relatively rarely, true organometallic compounds. Systematic studies have typically been carried out using metal alkyls and cyclopentadienyl-type compounds. 

Kim H (2003) Atomic layer deposition of metal and nitride thin films. Current research efforts and applications for semiconductor device processing. Journal of Vacuum Science Technology B 21(6), 2231-2261... 

In earlier work, no molecular structural data were available on mononuclear M amides, but this has changed markedly in the last three (and particularly last two) decades. Another significant development has been the use of the title compounds, and especially the homoleptic dimethylamides M(NMe2)3, as reagents, or synthons for the preparation of bridging binuclear imides 7 (Section 10.3) or cluster imides (e.g. 3 7) (Section 10.4), or Bi[N(SiMe3)2]3 as a precursor for atomic layer deposition.Heteroleptic amidometal chlorides have featured as precursors to cationic metal(III) amides (Section 10.2.4). 

Recently, low-temperature routes have been sought for by decomposition of organometallic complexes with tellurium-containing ligands. The optoelectronic devices normally require the material to be used as thin films. They are fabricated with special methods, such as molecular beam epitaxy, metal-organic chemical vapour deposition, or atomic layer deposition. 

This chapter is intended to cover major aspects of the deposition of metals and metal oxides and the growth of nanosized materials from metal enolate precursors. Included are most types of materials which have been deposited by gas-phase processes, such as chemical vapor deposition (CVD) and atomic layer deposition(ALD), or liquid-phase processes, such as spin-coating, electrochemical deposition and sol-gel techniques. Mononuclear main group, transition metal and rare earth metal complexes with diverse /3-diketonate or /3-ketoiminate ligands were used mainly as metal enolate precursors. The controlled decomposition of these compounds lead to a high variety of metal and metal oxide materials such as dense or porous thin films and nanoparticles. Based on special properties (reactivity, transparency, conductivity, magnetism etc.) a large number of applications are mentioned and discussed. Where appropriate, similarities and difference in file decomposition mechanism that are common for certain precursors will be pointed out. 

M. D. Groner, J. W. Elam, F. H. Fabreguette, and S. M. George, "Electrical Characterization of Thin AI2O3 Films Grown by Atomic Layer Deposition on Silicon and Various Metal Substrates," Thin Solid Films, 413 (2002) 186-197. 

More recently, atomic layer deposition (ALD) has been pnrsned in deep nanostructures by Reijnen (2001) and Meester (2001). Gaseous metal-organic precursors... 

Preparation of noble metal catalysts by atomic layer deposition FTIR studies... 

Atomic layer deposition (ALD, also known e.g. as ALE) is a material depositing technique originally developed for the processing of thin films. The technique is based on alternating selfisaturating gas-solid reactions in which vaporized active metal precursor is brought into contact with the support [1]. 

Several techniques have been developed to deposit alumina films on different surfaces such as those of semiconductors or metals. These films find apphcation in various areas. In most cases, amorphous alumina films are desired. Depending on the deposition techniques, various precursors may be used the following combinations have been reported plasma-enhanced atomic layer deposition using trimethylaluminum (112), metal-organic chemical vapor deposition using aluminum tri-iso-propoxide (113), and condensation from the gas phase using laser-evaporated alumina (114). Similar evaporation techniques can also be apphed to prepare Y-AI2O3 powders (115,116). 

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