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- Törndahl, Tobias, 1974-
(författare)
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Atomic Layer Deposition of Copper, Copper(I) Oxide and Copper(I) Nitride on Oxide Substrates
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Thin films play an important role in science and technology today. By combining different materials, properties for specific applications can be optimised. In this thesis growth of copper, copper(I) oxide and copper(I) nitride on two different substrates, amorphous SiO2 and single crystalline α-Al2O3 by the so called Atomic Layer Deposition (ALD) techniques has been studied. This technique allows precise control of the growth process at monolayer level on solid substrates. Other characteristic features of ALD are that it produces films with excellent step coverage and good uniformity even as extremely thin films on complicated shaped substrates.Alternative deposition schemes were developed for the materials of interest. It was demonstrated that use of intermediate water pulses affected the deposition pathways considerably. By adding water, the films are thought to grow via formation of an oxide over-layer instead of through a direct reaction between the precursors as in the case without water.For growth of copper(I) nitride from Cu(hfac)2 and ammonia no film growth occurred without adding water to the growth process. The Cu3N films could be transformed into conducting copper films by post annealing. In copper growth from CuCl and H2 the water affected film growth on the alumina substrates considerably more than on the fused silica substrates. The existence of surface -OH and/or -NHx groups was often found to play an important role, according to both theoretical calculations and experimental results.
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- Törndahl, Tobias, et al.
(författare)
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Epitaxy of copper on α-Al2O3(0 0 1) by atomic layer deposition
- 2005
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Ingår i: Journal of Crystal Growth. - : Elsevier BV. - 0022-0248. ; 276, s. 102-110
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Tidskriftsartikel (refereegranskat)abstract
- A combined X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) study have been carried out on copper films grown by atomic layer deposition at 400 °C. The copper films have been grown on single crystalline (0 0 1) oriented α-Al2O3 up to a thickness of 500 nm. The films were relaxed and the diffraction peak broadening in 2θ was mainly dependent on the copper grain size. Broadening of the diffraction peaks in ω was found to be related to defects (mosaicity and intrinsic microstrain). The deposited films were epitaxial and grew with the (1 1 1) plane in parallel to the substrate surface. Extensive twinning in the copper grains in different Cu1 1 1 directions occurred according to the TEM study, both in directions perpendicular to the substrate surface ([1 1 1] and ) and along other 1 1 1 directions as well. As an effect of a twin, an extra Cu(5 1 1) orientation was present in the XRD data.
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- Törndahl, Tobias, 1974-, et al.
(författare)
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Growth of Copper(I) Nitride by ALD Using Copper(II) Hexafluoroacetylacetonate, Water and Ammonia as Precursors
- 2006
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 153:3, s. C146-C151
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Films of copper(I) nitride were deposited by atomic layer deposition (ALD) using copper(II) hexafluoroacetylacetonate, water, and ammonia as precursors. Introduction of a water pulse in the ALD cycle was found to be crucial for initiating film growth on both amorphous SiO2 and single-crystalline α-Al2O3(001) substrates. The water pulses generated an oxidic copper monolayer, which in a subsequent ammonia pulse was converted to the nitride. The films have been grown in the temperature range from 210to302°C . Phase pure films of Cu3N were obtained up to 265°C . At higher deposition temperatures such as 283°C , phase mixtures of Cu3N and Cu were obtained. For temperatures above 302°C films of only Cu were grown. Film growth rate was the same on the two different substrates. The films were randomly oriented on SiO2 . Completely intact films were obtained at a thickness of 20nm . The optical bandgap of the films was measured to be 1.6eV .
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