Yttrium tris(hexafluoracetylacetonate) Y(hfac)3

Y(hfac)3 (and for comparison Y(thd)3) was used as yttrium source for the preparation  of high-k dielectric Y2O3 layers by oxygen-plasma assisted MOCVD at 350-450°C deposition temperature; Y(hfac)3 precursor was evaporated at 140-150°C/0.3mbar. F-containing precursor Y(hfac)3 resulted in the Y2O3 layers having unacceptable large hysteresis in capacitance-voltage data (possibly due to the F incorporation) [[i]]

[i] D. Niu, R. W. Ashcraft, Z. Chen, S. Stemmer, G. N. Parsons , J. Electrochem. Soc., Vol. 150, Iss. 5, pp. F102-F109 (2003), “Chemical, Physical, and Electrical Characterizations of Oxygen Plasma Assisted Chemical Vapor Deposited Yttrium Oxide on Silicon”

Yttrium tris(2,2,6,6-tetramethyl-3,5-heptanedionate) Y(thd)3

Yttrium tris(2,2,6,6-tetramethyl-3,5-heptanedionate) Y(thd)3 (or Y(DPM)3 (DPM=dipivaloylmethanate) is conventional precursor for the growth of Y-containing high temperature superconductor layers by MOCVD [[i]] and electroluminescent Y2O3 [[ii]]. However, it has some disadvantages for MOCVD applications: Y(thd)3 is a solid at room temperature (not convenient to use in flash vaporization systems), also it is not very stable in a heated bubbler (leading to difficulty to obtain a reproducible concentration of its vapors).

High purity Y(thd)3was successfully synthesized from inorganic Y salts and HDPM in ethanol/aqueous solution, purified by recrystallization from toluene and characterized by elemental analysis, XRD, TGA/DTA, NMR and FTIR spectroscopy (both fresh and aged for 30 days in air), Y(thd)3was applied as precursor of MOCVD of Y-containing multi-component oxide thin films. [[iii][PS1] ]

Vapor pressure and vapor molecular weight of Y(thd)3 (Y(C11H19O2)3) were measured by a torsion-effusion/mass-loss method in the ranges (346 to 375) K and (361 to 387) K, respectively. The molecular weight data indicate that the saturated vapor of Y(thd)3 precursor is highly monomeric. Vapor pressures, estimated to be accurate within 5% was  presented in equation form for reliable extrapolation to higher temperatures.  [[iv]]

The TGA curve of Y(thd)3 precursor is presented in Fig. The most of the precursor is evaporating between 188 and 255°C, only a small residue (2.6%) is left non-evaporated.

[i] H. Meinem, K. Timmer, H.L. Linden, C.I.M.A. Spee, Mat. Res. Soc. Symp. Proc., 335, 193-201, 1994

[ii] G.A. Hirata, J. McKittrick, M. Avalos-Borja, J.M. Siqueros, D. Devlin, Appl. Surf. Sci, 1997, 113/114, 509-514

[iii]H. Song, Y. Jiang, Ch. Xia, G. Meng, D. Peng, https://doi.org/10.1016/S0022-0248(02)02413-2, https://www.sciencedirect.com/science/article/pii/S0022024802024132

“Synthesis and characterization of volatile metal β-diketonate chelates of M(DPM)n (M=Ce, Gd, Y, Zr, n=3,4) used as precursors for MOCVD”

[iv] C. Colominas, K. H. Lau, D. L. Hildenbrand, S. Crouch-Baker, A. Sanjurjo, J. Chem. Eng. Data, 2001, 46 (2), p.446–450, DOI: 10.1021/je0003445, “Vapor Pressures of the Copper and Yttrium β-Diketonate MOCVD Precursors”, http://pubs.acs.org/doi/abs/10.1021/je0003445 

Y(thd)3 for Y2O3 by CECVD

Y(thd)3 is a useful precursor for the growth of thin films of yttria Y2O3 by CECVD for potential applications as electronic insulators, coatings, reaction barriers and superconducting materials[[i]]

[i]Y. Zhang, R. Puddephatt, Chem. Mater.11, 148, (1999)

Y(thd)3 for Y2O3 oxygen-plasma assisted MOCVD

Y(thd)3 (and for comparison Y(hfac)3) was applied as Y precursor for the growth of high-k dielectric Y2O3 layers by oxygen-plasma assisted MOCVD at 350-450°C deposition temperature; air-exposed Y2O3 layers grown with Y(thd)3  after annealing exhibited triple layer structure having stoichiometric Y2O3 on top and yttrium silicate/SiO2 at dielectric/Si interface, as found by TEM, XPS and EELS (electron energy loss spectroscopy) and confirmed by FTIR, XRD and AFM; the reaction with the Si substrate was impeded by prenitridation of the silicon surface, which promoting the Y2O3 structure. [[i]]

[i] D. Niu, R. W. Ashcraft, Z. Chen, S. Stemmer, G. N. Parsons , J. Electrochem. Soc., Vol. 150, Iss. 5, pp. F102-F109 (2003), “Chemical, Physical, and Electrical Characterizations of Oxygen Plasma Assisted Chemical Vapor Deposited Yttrium Oxide on Silicon”

Y(thd)3 for Y2O3, YSiOx by liquid injection PE MOCVD

    Y(thd)3 (vaporised at 190°C/2.7mbar) was applied as Y source for the deposition of amorphous YSiO and Y2O3 layers at 350-450°C by the liquid injection plasma-enhanced MOCVD (the combined approach has advantages: plasma assistance enables deposition at a much lower substrate temperature, whereas pulsed-liquid precursor delivery allows an accurate control of the supplied reactive species). Yttrium silicate YSiOx or yttrium oxide Y2O3  layers were formed depending on the deposition temperature: ultrathin Y2O3 deposition was performed at temperature <380 °C; according to the XPS the films contained carbon contamination that was reduced by increasing the growth temperature. Plasma played a key role in the deposition mechanisms and chemical structure of the films and interface. The injection frequency (i.e., reactive species supply rate) played a significant role in the silicate and interface formation: high injection frequency limited the formation of SiO2 interfacial layer (and therefore YSiOx  silicate layer) and favored the growth of Y2O3 (as determined by angle-resolved XPS). As-deposited at 350°C Y2O3 films had low leakage current (J<10−7 A/cm2) and high breakdown field (∼8 MV/cm).[[i]]

[i] C.Durand, C.Dubourdieu, C.Vallée, V.Loup, M. Bonvalot, O. Joubert, H. Roussel,O. Renault, J. Appl. Phys. 2004 , 96, 1719; http://dx.doi.org/10.1063/1.1766412, “Microstructure and electrical characterizations of yttrium oxide and yttrium silicate thin films deposited by pulsed liquid-injection plasma-enhanced metal-organic chemical vapor deposition”

Y(thd)3 for YBa2Cu3O7-x by MOCVD

   Yttrium tris(2,2,6,6-tetramethyl-3,5-heptanedionate) Y(thd)3 (in conjunction with barium and copper(II) β-diketonates) was applied for the MOCVD deposition of YBa2Cu3O7−δ superconducting thin films [[i]]

 [i] G. B Deacon, P. MacKinnon, R. S Dickson, G. N Pain, B. O West, “Applied Organometallic Chemistry, 1990, Vol. 4, Iss. 5, p.439–449, DOI: 10.1002/aoc.590040504 “CVD of metal organic and other rare-earth compounds”

Yttrium tris(2,2,6,6-tetramethyl-3,5-heptanedionate) bipyridyl adduct Y(thd)3(bipy)

Yttrium tris(2,2,6,6-tetramethyl-3,5-heptanedionate) 1,10-phenantroline adduct Y(thd)3(phen)

Y(thd)3(bipy) , Y(thd)3(phen)  (and for comparison Y(thd)3 )  have been applied as ALD precursors for the growth of cubic Y2O3 films on soda lime glass and Si(100)  at 200-425°C temperature; ozone O3 was used as oxidant. The precursor evaporation conditions were following: Y(thd)3 at 120°C/2-3 mbar, Y(thd)3(bipy) at 130°C/2-3 mbar, and Y(thd)3(phen) at 180°C/2-3 mbar. With all precursors, a deposition rate of 0.22–0.23 Å/cycle was obtained at 250–350 °C on both substrates, indicating a surface-controlled growth and similar surface species at the deposition temperatures used. Crystalline (100) preferentially oriented Y2O3 films were obtained within ALE deposition window (temperature range of 250–375 °C), whereas nearly amorphous films were deposited at temperatures <250 °C. At deposition temperatures slightly above the ALE window (375 °C), where a partial decomposition of Y(thd)3 probably takes place (judging on impurity levels and growth rates), preferential orientation of Y2O3 layers changed from (100) to (111); the adducting of Y(thd)3 did not bring any advantages in the ALE growth of Y2O3.Deposited Y2O3 layers were characterized by XRD (crystallinity), AFM (surface morphology), ion-beam analysis/ XPS (stoichiometry and impurity levels) and IR measurements (to determine the type of carbon impurity) [[i]]

[i] M. Putkonen, T. Sajavaara, L.-S. Johansson, L. Niinistö, Chem. Vap. Dep., 2001,Vol. 7, Iss.1, p.44–50; “Low-Temperature ALE Deposition of Y2O3 Thin Films from β-Diketonate Precursors”, DOI: 10.1002/1521-3862(200101)7:1<44::AID-CVDE44>3.0.CO;2-Q

Yttrium tris(6,6,7,7,8,8,8-heptafluoro- 2,2-dimethyl-3,5-octanedionate) Y(fod)3

    Yttrium 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate  Y(fod)3 (in conjunction with barium and copper(II) β-diketonates) was mentioned to have been tested to deposit YBa2Cu3O7−δ as superconducting thin films by MOCVD [[i]]

[i] G. B Deacon, P. MacKinnon, R. S Dickson, G. N Pain, B. O West, “Applied Organometallic Chemistry, 1990, Vol. 4, Iss. 5, p.439–449, DOI: 10.1002/aoc.590040504 “CVD of metal organic and other rare-earth compounds”

Yttrium tris(2,7,7-trimethyl-3,5-octanedionate) Y(tod)3

    Y(tod)3, a complex with new type of diketonate ligand, has been successfully used as Y precursor (in combination with Hf(tod)4) for the pulsed liquid injection (PLI) MOCVD growth of Y-stabilized HfO2 (YSH) layers; the precursor Y(tod)3 was vaporised at 280°C/6.7mbar. The growth rate was significantly higher especially at lower temperatures, compared to the conventional precursor system Y(thd)3 + Hf(thd)4. The grown YSH films were characterized by XRD, XPS, EDS and AFM; highly textured and in-plane oriented films were deposited on sapphire by liquid injection MOCVD. [[i]]

 [i] Sergej V. Pasko, Liliane G. Hubert-Pfalzgraf, Adulfas Abrutis, Philippe Richard, Ausrine Bartasyte and Vida Kazlauskiene, J . M a t e r . C h e m . , 2 0 0 4 , 1 4 , 1 2 4 5 – 1 2 5 1 , « New sterically hindered Hf, Zr and Y b-diketonates as MOCVD precursors for oxide films »

Yttrium tris(2,2,6,6-tetramethyl-3,5-octadionato) Y(tmod)3

Yttrium tris(2,2,6,6-tetramethyl-3,5-octadionato) tetraglyme adduct Y(tmod)3(tetraglyme)

Y(tmod)3 and Y(tmod)3(tetraglyme) were compared as potential yttrium MOCVD precursors, by using thermogravimetric (“TG-DTA) analysis. The adducted molecule Y(tmod)3(tetraglyme) was a liquid and left no residue after full evaporation (which finishes at ca. 320°C), whereas the unadducted molecule Y(tmod)3 is solid. The TGA-DTA curves for Y(tmod)3(tetraglyme) are shown in Fig. [i]

[i] C Dussarrat, US Patent App. 12/536,804, 2009 , « NOVEL LANTHANIDE BETA-DIKETONATE PRECURSORS FOR LANTHANIDE THIN FILM DEPOSITION »

www.google.de/patents?id=mQ7MAAAAEBAJ&pg=PA11&zoom=4&dq=%22Gd%28TMOD%293%22&output=text#c_top

Tris(6-ethyl-2,2-dimethyl-3,5-decanedionato) yttrium Y(EDMDD)3

Tris(6-ethyl-2,2-dimethyl-3,5-decanedionato) yttrium Y(EDMDD)3 (M = 764.96) is  pale yellow liquid at RT, slightly reacting with H2O.

Y(EDMDD)3  was proposed as potential yttrium MOCVD precursor [[i]]

[i]ADEKA 2008

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