Huazhi Li

Atomic Layer Deposition of Lanthanum-Based Ternary Oxides

Lanthanum-based ternary oxide La x M 2-x O 3 (M = Sc, Lu, or Y) films were deposited on HF-last Si substrates by atomic layer deposition. Both LaScO 3 and LaLuO 3 films are amorphous while the as-deposited La x Y 2-x O 3 films form a polycrystalline layer/ amorphous layer structure on Si. Transmission electron microscopy and electrical analysis show the absence of interfacial layers. The dielectric constants for LaScO 3 , LaLuO 3 , and La 1.23 Y 0.77 O 3 films are ∼23, 28 ± 1, and 17 ± 1.3, respectively, with leakage current density up to 6 orders of magnitude lower than that of thermal SiO 2 with the same effective oxide thickness. Conformal coating thickness is demonstrated on holes with aspect ratio ∼80:1.

Effects of O3 and H2O oxidants on C and N-related impurities in atomic-layer-deposited La2O3 films observed by in situ x-ray photoelectron spectroscopy

The effect of H2O and O3 oxidants on the behavior of residual C and N-related impurities as well as Si out-diffusion and interfacial layer formation in atomic-layer-deposited La2O3 films grown at 250 °C were examined using in situ x-ray photoelectron spectroscopy. The silicate formation was suppressed in a La2O3 film grown using O3 compared to that deposited using H2O, but interfacial layer growth was enhanced. The accumulation of C and N-related residues with low binding energy, which originated from incomplete reactions, was suppressed in La2O3 films grown using O3. However, the use of O3 resulted in La-carbonate phase in film.

Synthesis and Characterization of Ruthenium Amidinate Complexes as Precursors for Vapor Deposition

Three new ruthenium amidinate complexes were prepared: tris(diisopropylacetamidinato)-ruthenium(III), Ru( i PrNC(Me)N i Pr)3 4; bis(diisopropyl-acetamidinato)ruthenium(II) dicarbonyl, Ru( i PrNC(Me)N i Pr)2(CO)2 5; and bis(di- tert-butylacetamidinato)ruthenium(II) dicarbonyl, Ru( t BuNC(Me)N t Bu)2(CO)2 6. They have been synthesized and charac- terized by 1 H NMR, TG and X-ray structure analysis. These three complexes were found to be monomeric and air stable. Compound 6 was found to have sufficient volatility and thermal stability for use in chemical vapor deposition (CVD) and atomic layer deposition (ALD) of ruthenium metal films.

Effects of Low Temperature O2 Treatment on the Electrical Characteristics of Amorphous LaAlO3 Films by Atomic Layer Deposition

Citation Liu, Yiqun, Hoon Kim, Jun-Jieh Wang, Huazhi Li, and Roy G.Gordon. 2008. Effects of low temperature O2 treatment on theelectrical characteristics of amorphous LaAlO3 films by atomiclayer deposition. Physics and Technology of High-k GateDielectrics. Special Issue, ECS Transactions 16, no. 5: 471-478.Published Version doi:10.1149/1.2981628Accessed September 28, 2011 6:29:20 AM EDTCitable Link http://nrs.harvard.edu/urn-3:HUL.InstRepos:3353948Terms of Use This article was downloaded from Harvard Universitys DASHrepository, and is made available under the terms and conditionsapplicable to Other Posted Material, as set forth athttp://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#LAA

ALD of lanthanum aluminate using lanthanum formamidinate precursor

The physical and electrical characteristics of La 2 O 3 and LaAlO 3 films, deposited by atomic layer deposition (ALD) and using a new La formamidinate precursor (La-FAMD), were investigated. The La-FAMD precursor has superior thermal stability and is also the most volatile La source available today. The vapor pressure of La-FAMD, maintained at 100 oC, is approximately 60 times higher than the commercial available source La-THD (THD = tetramethylheptanedionato).

Novel Zirconium Formamidinate Precursor for the ALD of ZrO 2

Zirconium tetrakis( N,N ’-dimethylformamidinate), Zr-FAMD, was synthesized and evaluated as a precursor for the deposition of zirconium oxide (zirconia) thin films via Atomic Layer Deposition (ALD) technique. Zr-FAMD has a high vapor pressure and displays an exceptionally high thermal stability; it is thus well-suited to be used as a precursor for the deposition of zirconia thin films. Zr-FAMD is a more ideally-suited precursor than tetrakisethylmethylaminozirconium or TEMAZr, which has an equivalent vapor pressure, but is plagued with a rather low thermal stability, limiting its usefulness at high deposition temperatures. Zr-FAMD can be used to deposit zirconia thin films at temperatures as high as 375 °C without evidence of decomposition.