| 1. |
- Dezelah, Charles L., et al.
(författare)
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A low valent metalorganic precursor for the growth of tungsten nitride thin films by atomic layer deposition
- 2007
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 17:11, s. 1109-1116
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Tidskriftsartikel (refereegranskat)abstract
- The atomic layer deposition growth of tungsten nitride films was demonstrated using the precursors W-2(NMe2)(6) and ammonia with substrate temperatures between 150 and 250 degrees C. At 180 degrees C, surface saturative growth was achieved with W-2(NMe2)(6) pulse lengths of >= 2.0 s. The growth rates were between 0.74 and 0.81 angstrom cycle(-1) at substrate temperatures between 180 and 210 degrees C. Growth rates of 0.57 and 0.96 angstrom cycle(-1) were observed at 150 and 220 degrees C, respectively. In a series of films deposited at 180 degrees C, the film thicknesses varied linearly with the number of deposition cycles. Films grown at 180 and 210 degrees C exhibited resistivity values between 810 and 4600 mu Omega cm. Time-of-flight elastic recoil detection analysis on tungsten nitride films containing a protective AlN overlayer demonstrated slightly nitrogen-rich films relative to W2N, with compositions of W1.0N0.82C0.13O0.26H0.33 at 150 degrees C, W1.0N0.74C0.20O0.33H0.28 at 180 degrees C, and W1.0N0.82C0.33O0.18H0.23 at 210 degrees C. In the absence of an AlN overlayer, the oxygen and hydrogen levels were much higher, suggesting that the films degrade in the presence of ambient atmosphere. The as-deposited films were amorphous. Amorphous films containing a protective AlN overlayer were annealed to 600 - 800 degrees C under a nitrogen atmosphere. X-Ray diffraction patterns suggested that crystallization does not occur at or below 800 degrees C. Similar annealing of films that did not contain the AlN overlayer afforded X-ray diffraction patterns that were consistent with orthorhombic WO3. Atomic force microscopy showed root-mean-square surface roughnesses of 0.9, 0.8, and 0.7 nm for films deposited at 150, 180, and 210 degrees C, respectively.
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| 2. |
- Dezelah, Charles L., et al.
(författare)
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The Atomic Layer Deposition of HfO2 and ZrO2 using Advanced Metallocene Precursors and H2O as the Oxygen Source
- 2008
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Ingår i: Chemical Vapor Deposition. - : Wiley. - 0948-1907 .- 1521-3862. ; 14:11-12, s. 358-365
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Tidskriftsartikel (refereegranskat)abstract
- The atomic layer deposition (ALD) of HfO2 and ZrO2 thin films is investigated using (MeCp)(2)HfMe2, (MCp)(2)Hf(OMe)(Me), (MeCp)(2)ZrMe2, and (MeCp)(2)Zr(OMe)(Me) as the precursors at deposition temperatures between 300 and 500 degrees C, with water vapor as the oxygen Source. A self-limiting growth mechanism is confirmed at 350 degrees C for all the metal precursors examined. The processes provide nearly stoichiometric HfO2 and ZrO2 films with carbon and hydrogen concentrations below 0.5 and 1.0 at.-%, respectively, for representative samples. All films are polycrystalline as deposited, and possess a thin interfacial SiO2 layer. The capacitance-voltage (C-V) and Current density-voltage (I-V) behavior is reported and discussed for capacitor structures containing films from this study.
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| 3. |
- Niinisto, Jaakko, et al.
(författare)
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Advanced cyclopentadienyl precursors for atomic layer deposition of ZrO2 thin films
- 2008
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 18:28, s. 3385-3390
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Tidskriftsartikel (refereegranskat)abstract
- ZrO2 thin films were grown onto silicon (100) substrates by atomic layer deposition (ALD) using novel cyclopentadienyl-type precursors, namely (CpMe)(2)ZrMe2 and (CpMe)(2)Zr(OMe) Me (Cp = cyclopentadienyl, C5H5) together with ozone as the oxygen source. Growth characteristics were studied in the temperature range of 250 to 500 degrees C. An ALD-type self-limiting growth mode was verified for both processes at 350 degrees C where highly conformal films were deposited onto high aspect ratio trenches. Signs of thermal decomposition were not observed at or below 400 degrees C, a temperature considerably exceeding the thermal decomposition temperature of the Zr-alkylamides. Processing parameters were optimised at 350 degrees C, where deposition rates of 0.55 and 0.65 angstrom cycle(-1) were obtained for (CpMe)(2)ZrMe2/O-3 and (CpMe)(2)Zr(OMe)Me/O-3, respectively. The films grown from both precursors were stoichiometric and polycrystalline with an increasing contribution from the metastable cubic phase with decreasing film thickness. In the films grown from (CpMe)(2)ZrMe2, the breakdown field did not essentially depend on the film thickness, whereas in the films grown from (CpMe)(2)Zr(OMe)Me the structural homogeneity and breakdown field increased with decreasing film thickness. The films exhibited good capacitive properties that were characteristic of insulating oxides and did not essentially depend on the precursor chemistry.
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