Search results for "Atomic layer"
showing 10 items of 140 documents
Low Temperature Growth of High Purity, Low Resistivity Copper Films by Atomic Layer Deposition
2011
The atomic layer deposition of copper metal thin films was achieved using a three precursor sequence entailing Cu(OCHMeCH2NMe2)2, formic acid, and hydrazine. A constant growth rate of 0.47−0.50 A/cycle was observed at growth temperatures between 100 and 170 °C. The resulting films are high purity and have low resistivities.
Influence of titanium-substrate roughness on Ca–P–O thin films grown by atomic layer deposition
2013
Abstract Amorphous Ca–P–O films were deposited on titanium substrates using atomic layer deposition, while maintaining a uniform Ca/P pulsing ratio of 6/1 with varying number of atomic layer deposition cycles starting from 10 up to 208. Prior to film deposition the titanium substrates were mechanically abraded using SiC abrasive paper of 600, 1200, 2000 grit size and polished with 3 μm diamond paste to obtain surface roughness R rms values of 0.31 μm, 0.26 μm, 0.16 μm, and 0.10 μm, respectively. The composition and film thickness of as-deposited amorphous films were studied using Time-Of-Flight Elastic Recoil Detection Analysis. The results showed that uniform films could be deposited on ro…
Nucleation and growth of ZnO on PMMA by low-temperature atomic layer deposition
2015
ZnO films were grown by atomic layer deposition at 35 °C on poly(methyl methacrylate) substrates using diethylzinc and water precursors. The film growth, morphology, and crystallinity were studied using Rutherford backscattering spectrometry, time-of-flight elastic recoil detection analysis, atomic force microscopy, scanning electron microscopy, and x-ray diffraction. The uniform film growth was reached after several hundreds of deposition cycles, preceded by the precursor penetration into the porous bulk and island-type growth. After the full surface coverage, the ZnO films were stoichiometric, and consisted of large grains (diameter 30 nm) with a film surface roughness up to 6 nm (RMS). T…
Atomic layer deposition of ferroelectric LiNbO3
2013
The ferroelectric and electro-optical properties of LiNbO3 make it an important material for current and future applications. It has also been suggested as a possible lead-free replacement for present PZT-devices. The atomic layer deposition (ALD) technique offers controlled deposition of films at an industrial scale and thus becomes an interesting tool for growth of LiNbO3. We here report on ALD deposition of LiNbO3 using lithium silylamide and niobium ethoxide as precursors, thereby providing good control of cation stoichiometry and films with low impurity levels of silicon. The deposited films are shown to be ferroelectric and their crystalline orientations can be guided by the choice of…
Plasma etch characteristics of aluminum nitride mask layers grown by low-temperature plasma enhanced atomic layer deposition in SF6 based plasmas
2012
The plasma etch characteristics of aluminum nitride (AlN) deposited by low-temperature, 200 °C, plasma enhanced atomic layer deposition (PEALD) was investigated for reactive ion etch (RIE) and inductively coupled plasma-reactive ion etch (ICP-RIE) systems using various mixtures of SF6 and O2 under different etch conditions. During RIE, the film exhibits good mask properties with etch rates below 10r nm/min. For ICP-RIE processes, the film exhibits exceptionally low etch rates in the subnanometer region with lower platen power. The AlN film’s removal occurred through physical mechanisms; consequently, rf power and chamber pressure were the most significant parameters in PEALD AlN film remova…
Stabilizing organic photocathodes by low-temperature atomic layer deposition of TiO2
2017
Organic semiconductor light absorbers are receiving attention for their potential application in photoelectrochemical (PEC) cells for renewable fuels generation. Key to their advancement is precise control of the interfaces between charge-selective contacts, absorber layers, and electrocatalysts, while maintaining compatibility with an aqueous electrolyte environment. Here we demonstrate a new process for low-temperature atomic layer deposition (ALD) of TiO2 onto a P3HT:PCBM polymer blend surface for stable high-performance organic PEC photocathodes. This ALD TiO2 layer provides three key functions: (1) formation of an electron-selective contact to the polymer to enable photovoltage and pho…
Aluminum oxide from trimethylaluminum and water by atomic layer deposition:The temperature dependence of residual stress, elastic modulus, hardness a…
2014
Use of atomic layer deposition (ALD) in microelectromechanical systems (MEMS) has increased as ALD enables conformal growth on 3-dimensional structures at relatively low temperatures. For MEMS device design and fabrication, the understanding of stress and mechanical properties such as elastic modulus, hardness and adhesion of thin film is crucial. In this work a comprehensive characterization of the stress, elastic modulus, hardness and adhesion of ALD aluminum oxide (Al2O3) films grown at 110-300 C from trimethylaluminum and water is presented. Film stress was analyzed by wafer curvature measurements, elastic modulus by nanoindentation and surface-acoustic wave measurements, hardness by na…
Tailoring of the electronic properties of ZnO-polyacrylonitrile nanofibers: Experiment and theory
2017
Abstract We report the study of ZnO-polyacrylonitrile (ZnO-PAN) nanofibers fabricated by the combination of electrospinning and atomic layer deposition. The latter technique enables us to control the size of the surface of ZnO 1D nanostructures and hence its effectiveness for energy and biosensor applications. We observe the tendency of ZnO to form nanograins with increase of the layer thickness, and investigate the influence of the grain size on the electronic properties of the nanofibers. It is demonstrated that the ZnO work function (Φ) is strongly affected by surface band bending in the ZnO layer. The observed change of Φ in ZnO layers results from the curvature of the grain surface as …
Thin film growth into the ion track structures in polyimide by atomic layer deposition
2017
Abstract High-aspect ratio porous structures with controllable pore diameters and without a stiff substrate can be fabricated using the ion track technique. Atomic layer deposition is an ideal technique for depositing thin films and functional surfaces on complicated 3D structures due to the high conformality of the films. In this work, we studied Al2O3 and TiO2 films grown by ALD on pristine polyimide (Kapton HN) membranes as well as polyimide membranes etched in sodium hypochlorite (NaOCl) and boric acid (BO3) solution by means of RBS, PIXE, SEM-EDX and helium ion microcopy (HIM). The focus was on the first ALD growth cycles. The areal density of Al2O3 film in the 400 cycle sample was det…
Characterization of ALD grown Ti x Al y N and Ti x Al y C thin films
2017
Abstract Atomic layer deposition (ALD) was used to grow Ti x Al y N and Ti x Al y C thin films using trimethylaluminum (TMA), titanium tetrachloride and ammonia as precursors. Deposition temperature was varied between 325 °C and 500 °C. Films were also annealed in vacuum and N 2 -atmosphere at 600–1000 °C. Wide range of characterization methods was used including time-of-flight elastic recoil detection analysis (ToF-ERDA), X-ray diffractometry (XRD), X-ray reflectometry (XRR), Raman spectroscopy, ellipsometry, helium ion microscopy (HIM), atomic force microscopy (AFM) and 4-point probe measurement for resistivity. Deposited films were roughly 100 nm thick and contained mainly desired elemen…