Thermal Metalorganic Chemical Vapor Deposition of Ti-Si-N Films for Diffusion Barrier Applications

Structurally disordered refractory ternary films such as titanium silicon nitride (Ti-Si-N) have potential as advanced diffusion barriers in future ULSI metallization schemes. Here the authors present results on purely thermal metalorganic chemical vapor deposition (CVD) of Ti-Si-N. At temperatures between 300 and 450 C, tetrakis(diethylamido)titanium (TDEAT), silane, and ammonia react to grow Ti-Si-N films with Si contents of 0--20 at.%. Typical impurity contents are 5--10 at.%H and 0.5 to 1.5 at.% C, with no O or other impurities detected in the bulk of the film. Although the film resistivity increases with increasing Si content, it remains below 1,000 {micro}{Omega}-cm for films with less than 5 at.% Si. These films are promising candidates for advanced diffusion barriers

Thermal metalorganic chemical vapor deposition of Ti-Si-N films for diffusion barrier applications

Structurally disordered refractory ternary films such as titanium silicon nitride (Ti-Si-N) have potential as advanced diffusion barriers in future ULSI metallization schemes. Here the authors present results on purely thermal metalorganic chemical vapor deposition (CVD) of Ti-Si-N. At temperatures between 300 and 450 C, tetrakis(diethylamido)titanium (TDEAT), silane, and ammonia react to grow Ti-Si-N films with Si contents of 0--20 at.%. Typical impurity contents are 5--10 at.%H and 0.5 to 1.5 at.% C, with no O or other impurities detected in the bulk of the film. Although the film resistivity increases with increasing Si content, it remains below 1,000 {micro}{Omega}-cm for films with less than 5 at.% Si. These films are promising candidates for advanced diffusion barriers

Crystal structure and luminescence of 2,7-dimethylnaphthalene-1-carbonitrile

The title compound crystallizes in the monoclinic space group P21/c: Mr = 181.2; a = 7.119(1), b = 18.389(4), c = 7.5385(6) Å; β = 91.661(7)o; V = 986.4(5) Å3; and Z = 4. The purified material shows fluorescence similar to other naphthalene derivatives: monomer fluorescence (λmax 350-370 nm) in the solid state and in dilute solutions, and excimer fluorescence (λmax 421 nm) in concentrated solutions. Intense blue-green luminescence (λmax, 490 nm) is observed in some partially purified crystalline samples. This is attributed to phosphorescence from two isomeric bromodimethylnaphthalenecarbonitrile impurities detected by GC-MS analysis

Electronic spectrum and crystal structure of fac-MoOCl\u3csub\u3e3\u3c/sub\u3e(dppe)

X-ray analysis of the oxomolybdenum(V) complex MoOCl3(dppe) (dppe = 1,2-bis(diphenylphosphino)ethane) shows that it is the facial isomer. (C26H24Cl1MoOP2, space group P21/n, a = 13.217(1), b = 12.8935(8), c = 16.0578(9) Å, β= 99.967(5)°, V = 2695.1(6) Å3, Z = 4, R = 0.038 for 6228 data with l \u3e 1σ(I).) The electronic absorption spectrum of the title compound is also compared with those of other oxomolybdenum(V) complexes. © 1998 Elsevier Science Ltd. All rights reserved

Solution Photophysics, One-Electron Photooxidation, and Photoinitiated Two-Electron Oxidation of Molybdenum(III) Complexes

Several six-coordinate Mo(III) complexes phosphoresce and undergo photooxidation in room-temperature solution. The phosphorescence of (Me3[9]aneN3)MoX3 (Me3[9]aneN3 = 1,4,7-trimethyl-l,4,7-triazacyclononane) in CH3-CN at room temperature occurs with the following maxima, lifetimes, and quantum yields: X = Cl, 1120 nm, 1.0 μs, and 6.1 × 10-5; X = Br, 1130 nm, 0.80 μs, and 9.6 × 10-5; and X = I, 1160 nm, 0.40 μs, and 1.2 × 10-4, respectively. The phosphorescences are assigned to the {2Eg, 2T1g} → 4A2g transition. Solutions of HB(Me2pz)3MoIIICl3- Me2pzH = 3,5-dimethylpyrazole) in CH3CN, and solid MoCl3(py)3 and (Me3[9]aneN3)-WCl3, also phosphoresce. (Me3[9]aneN3)MoX3 (X = Cl, Br, I) complexes undergo reversible one-electron photooxidation upon irradiation in the presence of acceptors such as TCNE and chloranil. (Me3[9]aneN3)MoX3 (X = Br, I only) are photooxidized irreversibly to [(Me3[9]aneN3)MoIVX3]+ by C(NO2)4 in CH3CN. In CH3-CN-H2O (1:1 v/v), photoinitiated two-electron oxidation occurs: the primary photoproduct is Mo(IV), which disproportionates spontaneously to form [(Me3[9]aneN3)MovOX2]+

Structures of anhydrous and hydrated copper(II) hexafluoroacetylacetonate

Crystal structure analyses are reported for anhydrous copper(II) hexafluoroacetylacetonate (Cu(hfac)2) and for two of its hydrates. The anhydrous compound (Cu(hfac)2, 1: P1; at 100 K, a = 5.428(1), b = 5.849(1), c = 11.516(3) Å; α = 81.47(2), β = 74.57(2), γ = 86.96(2)°; Z = 1) contains centrosymmetric square-planar complexes with close intermolecular Cu···F contacts. The geometry of the complex is similar to that previously reported for Cu(hfac)2· toluene. The monoaquo compound (Cu(hfac)2(H2O), 2: P21/c; at 100 K, a = 10.8300(8), b = 6.5400(6), c = 21.551(3) Å; β = 90.282(8)°; Z = 4) consists of square-pyramidal molecules with apical H2O ligands, and close-lying F atoms in the sixth coordination sites. The major difference between this structure and the two other polymorphs previously reported is the nature and direction of hydrogen bonds. The yellow-green solid formed from Cu(hfac)2 with excess H2O is identified as the trihydrate. In crystalline form it is the previously unreported [trans-Cu(hfac)2-(H2O)2] ·H2O (3: P1; at 150 K, a = 8.3899(3), b = 9.6011(3), c = 11.4852(4) Å; α = 72.397(2), β = 79.161(2), γ = 87.843(2)°; Z = 2). There is no conclusive evidence in favor of any solid with the composition Cu(hfac)2· 2H2O

Electronic Absorption Spectra and Phosphorescence of Oxygen-Containing Molybdenum(IV) Complexes

Electronic absorption and emission spectra are reported for salts of two oxomolybdenum(IV) cations, [MoOCl-(CN-t-Bu)4]+ and [MoOCl(Ph2PCH2CH2PPh2) 2]+. and for the new Mo(IV) complex [trans-Mo(OCH3)2(CN-t-Bu)4]2+. All three ions show absorption bands (λmax.abs 550-570 nm; ∈ 45-120 M-1 cm-1) attributable to the 1A1[(dxy)2] → 1E[(dxy)1(dxz,yz)1] (C4v) transition, and the last two show weak shoulders in the 700-750 nm range due to the analogous spin-forbidden (1A1 → 3E) transition. Phosphorescence (λmax,em 850-960 nm) occurs in the solid state for all three compounds at both room temperature and 77 K, and for [MoOCl(CN-t-Bu)4]+ in CH2Cl2 at room temperature. These are the first phosphorescences recorded for molybdenum(IV) complexes. [MoOCl-(CN-t-Bu)4](BPh4) precipitates quickly if NaBPh4 is added to the Mo(IV) solution prepared from MoCl5 and tert-butyl isocyanide in CH3OH. However, if NaPF6 is used instead, [trans-Mo(OCH3)2(CN-t-Bu)4](PF 6)2 (formed by reaction of [MoOCl(CN-t-Bu)4]+ with methanol) crystallizes over a period of ca. 24 h. The crystal structure of [trans-Mo(OCH3)2(CN-t-Bu)4](PF 6)2 has been determined: C22H42F12MoN4O2P 2, monoclinic; space group P21/ c; a = 9.1538(8) Å, b = 15.709(2) Å, c = 13.456(2) Å; β= 103.31(1)°; Z = 2; R(F) = 0.063, RW(F) = 0.056 for 2719 reflections with I \u3e σ(I)