Customer Papers
This is a searchable database of papers written by our customers, using Cambridge NanoTech systems. If you are publishing a paper based on research done on a Cambridge NanoTech ALD system, please contact us. We would be pleased to include it in our database.Showing customer papers 1-10 of 39 Next
| LINK | Shim, J. H.; Chao, C. C.; Huang, H.; Prinz, F. B. |
| "Atomic layer deposition of yttria-stabilized zirconia for solid oxide fuel cells" | |
| Chemistry of Materials, 2007, 19, 3850-3854 | |
| Abstract: | Yttria-stabilized zirconia ( YSZ) films were synthesized by atomic layer deposition ( ALD). Tetrakis( dimethylamido)zirconium and tris( methylcyclopentadienyl) yttrium were used as ALD precursors with distilled water as oxidant. From X-ray photoelectron spectroscopy ( XPS) compositional analysis, the yttria content was identified to increase proportionally to the pulse ratio of Y/Zr. Accordingly, the target stoichiometry ZrO2/Y2O3) 0.92:0.08 was achieved. Crystal and grain structures of ALD YSZ films grown on amorphous Si3N4 were analyzed by X-ray diffraction ( XRD) and atomic force microscopy ( AFM). The microstructure of the polycrystalline films consisted of grains of tens of nanometers in diameter. To evaluate ALD YSZ films as oxide ion conductor, freestanding 60 nm films were prepared with porous platinum electrodes on both sides of the electrolyte. This structure served as a solid oxide fuel cell designed to operate at low temperatures. Maximum power densities of 28 mW/cm(2), 66 mW/ cm(2), and 270 mW/ cm2 were observed at 265 degrees C, 300 degrees C, and 350 degrees C, respectively. The high performance of thin film ALD electrolyte fuel cells is related to low electrolyte resistance and fast electrode kinetics. The exchange current density at the electrode-electrolyte interface was approximately 4 orders of magnitude higher compared to reference Pt-YSZ values. |
| Address: | Shim, JH Stanford Univ, Dept Mech Engn, Stanford, CA 94305 USA Stanford Univ, Dept Mech Engn, Stanford, CA 94305 USA Stanford Univ, Dept Mech Engn, Stanford, CA 94305 USA Stanford Univ, Dept Mat Sci |
| LINK | Daub, M.; Knez, M.; Goesele, U.; Nielsch, K. |
| "Ferromagnetic nanotubes by atomic layer deposition in anodic alumina membranes" | |
| Journal of Applied Physics, 2007, 101, - | |
| Abstract: | In this paper, two methods for the synthesis of magnetic nanotubes inside the pores of anodic alumina membranes by atomic layer deposition (ALD) are compared. The precursors were nickelocene or cobaltocene, and H2O or O-3. The first method consists of a three-step ALD cycle: First, the sample is exposed to the metal-organic precursor, subsequently to water, and finally, to hydrogen. In the second method, metal oxide is deposited by a conventional two-step ALD cycle. After the ALD process, the sample is reduced under hydrogen atmosphere. The magnetic nanotubes obtained by the second method have a smaller grain size and improved magnetic properties. The magnetic nanotubes with diameters ranging from 35 to 60 nm exhibit a preferential magnetization direction along the nanowire axis. The Ni or Co nanotubes with larger diameters (around 160 nm) show a nearly isotropic magnetic behavior, with the magnetic moments arranged in a vortex state at zero field. (C) 2007 American Institute of Physics. |
| Address: | Daub, M Max Planck Inst Microstruct Phys, Weinberg 2, D-06120 Halle, Germany Max Planck Inst Microstruct Phys, Weinberg 2, D-06120 Halle, Germany Max Planck Inst Microstruct Phys, D-06120 Halle, Germany |
| LINK | Jia, H. P.; Gross, E. K.; Wallace, R. M.; Gnade, B. E. |
| "Patterning effects on poly (3-hexylthiophene) organic thin film transistors using photolithographic processes" | |
| Organic Electronics, 2007, 8, 44-50 | |
| Abstract: | We explore the effects of conventional photo lithographic patterning of the active layer of poly (3-hexylthiophene) (P3HT) organic thin film transistors (OTFT) on device performance. The performance of the devices was monitored in each step of the patterning process. We successfully developed a patterning process which is compatible with plastic substrates and P3HT as the organic semiconductor. In this process, parylene and atomic layer deposition (ALD) Al2O3 were used as capping layers. Al2O3 and parylene/P3HT were etched using Al etchant and O-2 plasma reactive ion etching (RIE), respectively. The degradation occurred primarily during the ALD Al2O3 deposition and capping layer etching. There was a 30% degradation in mobility, a 1-2x reduction in drive current, and an increase in threshold voltage after the ALD Al2O3 deposition. In the capping layer etching, a near 50% degradation in mobility was observed. The patterned devices have a mobility of 0.02 cm(2)/V s, which is 1000x better than photo lithographically patterned P3HT OTFTs previously reported in the literature, and comparable to un-patterned P3HT devices. (C) 2006 Elsevier B.V. All rights reserved. |
| Address: | Gnade, BE Univ Texas, POB 830688,EC 33, Richardson, TX 75083 USA Univ Texas, POB 830688,EC 33, Richardson, TX 75083 USA Univ Texas, Richardson, TX 75083 USA |
| LINK | Holme, Timothy P.; Prinz, Fritz B. |
| "Atomic Layer Deposition and Chemical Vapor Deposition Precursor Selection Method Application to Strontium and Barium Precursors" | |
| The Journal of Physical Chemistry A, 2007, 111, 8147-8151 | |
| Abstract: | A new selection method for atomic layer deposition (ALD) or chemical vapor deposition (CVD) precursors is proposed and tested. Density functional theory was used to simulate Sr and Ba precursors, and several precursors were selected and used to grow films via ALD as test cases for the precursor selection method. The precursors studied were M(x)2 (M = Sr, Ba; x = tetramethylheptanedionate (tmhd), acetylacetonate (acac), hexafluoroacetylacetonate (hfac), cyclopentadienyl (H5C5), pentamethylcyclopentadienyl (Me5C5), n-propyltetramethylcyclopentadienyl (PrMe4C5), tris(isopropylcyclopentadienyl) ( H2C5), tris(isopropylcyclopentadienyl)(THF) ( H2C5)(OC4H8), tris(isopropylcyclopentadienyl)(THF)2 ( H2C5)(OC4H8)2, tris(tert-butylcyclopentadienyl) ( H2C5), tris(tert-butylcyclopentadienyl)(THF) ( H2C5)(OC4H8), heptafluoro-2,2-dimethyl-3,5-octanedionate (fod)). The energy required to break bonds between the metal atom and the ligands was calculated to find which precursors react most readily. In the case of tmhd and Cp precursors, the energy required to break bonds in the precursor ligand was studied to evaluate the most likely mechanism of carbon incorporation into the film. Trends for Ba and Sr followed each other closely, reflecting the similar chemistry among alkaline earth metals. The diketonate precursors have stronger bonds to the metals than the Cp precursors, but weaker bonds within the ligand, explaining the carbon contamination found in experimentally grown films. Atomic layer deposition of SrO was tested with Sr(tmhd)2 and Sr(PrMe4Cp)2 and oxygen, ozone, and water as oxygen sources. No deposition was measured with tmhd precursors, and SrO films were deposited with PrMe4Cp with a source temperature of 200 oC and at substrate temperatures between 250 and 350 oC with growth rates increasing for oxygen sources in this order: O2 < H2O < O2 H2O. The experimental results support the predictions based upon calculations: PrMe4Cp and Me5Cp precursors are expected to be the best precursors among those studied for Ba and Sr film growth. |
| Address: | Mechanical Engineering Department, Stanford University, 440 Escondido Mall Stanford, California 94305 |
| LINK | Williams, J. R.; DiCarlo, L.; Marcus, C. M. |
| "Quantum Hall Effect in a Gate-Controlled p-n Junction of Graphene" | |
| Science, 2007, 317, 638-641 | |
| Abstract: | The unique band structure of graphene allows reconfigurable electric-field control of carrier type and density, making graphene an ideal candidate for bipolar nanoelectronics. We report the realization of a single-layer graphene p-n junction in which carrier type and density in two adjacent regions are locally controlled by electrostatic gating. Transport measurements in the quantum Hall regime reveal new plateaus of two-terminal conductance across the junction at 1 and X times the quantum of conductance, e2/h, consistent with recent theory. Beyond enabling investigations in condensed-matter physics, the demonstrated local-gating technique sets the foundation for a future graphene-based bipolar technology. |
| Address: | 1 School of Engineering and Applied Science, Harvard University, Cambridge, MA 02138, USA 2 Department of Physics, Harvard University, Cambridge, MA 02138, USA. |
| LINK | Zhang, Xiao-Hong; Domercq, Benoit; Wang, Xudong; Yoo, Seunghyup; Kondo, Takeshi; Wang, Zhong Lin; Kippelen, Bernard |
| "High-performance pentacene field-effect transistors using Al2O3 gate dielectrics prepared by atomic layer deposition (ALD)" | |
| Organic Electronics, 2007, 8, 718-726 | |
| Abstract: | High-performance pentacene field-effect transistors have been fabricated using Al2O3 as a gate dielectric material grown by atomic layer deposition (ALD). Hole mobility values of 1.5 /- 0.2 cm2/V s and 0.9 /- 0.1 cm2/V s were obtained when using heavily n-doped silicon (n -Si) and ITO-coated glass as gate electrodes, respectively. These transistors were operated in enhancement mode with a zero turn-on voltage and exhibited a low threshold voltage (< -10 V) as well as a low sub-threshold slope (<1 V/decade) and an on/off current ratio larger than 106. Atomic force microscopy (AFM) images of pentacene films on Al2O3 treated with octadecyltrichlorosilane (OTS) revealed well-ordered island formation, and X-ray diffraction patterns showed characteristics of a \"thin film\" phase. Low surface trap density and high capacitance density of Al2O3 gate insulators also contributed to the high performance of pentacene field-effect transistors. |
| Address: | a Center for Organic Photonics and Electronics (COPE), School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States b Center for Organic Photonics and Electronics (COPE), School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States c Center for Organic Photonics and Electronics (COPE), School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, United States |
| LINK | Xiao-Hong Zhang; Benoit Domercq; Xudong Wang; Seunghyup Yoo; Takeshi Kondo; Zhong Lin Wang; Bernard Kippelen |
| "High performance organic field-effect transistors using high-Kappa dielectrics grown by atomic layer deposition (ALD)" | |
| , 2007, 6658, 66580T | |
| Abstract: | We report on high performance field-effect transistors fabricated with pentacene as an active material and Al2O3 as a gate dielectric material grown by atomic layer deposition (ALD). These transistors were operated in enhancement mode with a zero turn-on voltage and exhibited a low threshold voltage (< -10 V) as well as a low subthreshold slope (< 1 V/decade) and an on/off current ratio larger than 106. Hole mobility values of 1.5 ± 0.2 cm2/Vs were obtained when using heavily n-doped silicon (n -Si) as gate electrodes and substrates. Atomic force microscopy (AFM) images of pentacene films on Al2O3 treated with octadecyltrichlorosilane (OTS) revealed well-ordered island formation, and X-ray diffraction patterns showed characteristics of a \"thin film\" phase. Compared with thermally-grown SiO2, Al2O3 gate insulators have lower surface trap density and higher capacitance density, to which the high performance of pentacene field-effect transistors can be attributed. |
| Address: | Georgia Institute of Technology |
| LINK | Wheeler, D.; Seabaugh, A.; Froberg, L.; Thelander, C.; Wernersson, L. E. |
| "Electrical properties of HfO2/InAs MOS capacitors" | |
| , 2007, 1-2 | |
| Abstract: | In this work, the first investigation of Au/Ti/HfO2/InAs metal-oxide-semiconductor capacitors is reported. The HfO2 is deposited by atomic layer deposition and characterized by current-voltage and capacitance-voltage measurements. The effects of surface treatment, deposition temperature, post-deposition anneal, and film thickness on breakdown field, leakage current, capacitance, and frequency dispersion are studied with the aim of producing HfO2-InAs interfaces suitable for use in InAs-channel MOSFETs. |
| Address: | Department of Electrical Engineering, University of Notre Dame, USA Division of Solid State Physics, Lund University, Sweden |
| LINK | Tapily, Kanda; Jakes, Joseph; Stone, Donald; Shrestha, Pragya; Gu, Diefeng; Baumgart, Helmut; Elmustafa, Abdelmageed |
| "Nanomechanical Properties of High-K Dielectrics Grown by Atomic Layer Deposition" | |
| ECS Transactions, 2007, 11, 123-130 | |
| Abstract: | The challenges of reducing gate leakage current and dielectric breakdown beyond the 45 nm technology node has shifted engineers\' attention from SiO2 to higher dielectric constant materials also known as high-k materials such as HfO2 and Al2O3. Therefore, it is important to investigate the electrical and mechanical properties of these materials that are projected to replace SiO2. In this study, HfO2 and Al2O3 have been deposited by atomic layer deposition (ALD) on Si wafers. Using continuous stiffness method (CSM) Nanoindenter® XP, we report elasto-mechanical properties of HfO2 and Al2O3 on Si. HfO2 has a hardness and modulus of 9-10 {plus minus} 2 GPA and 200 {plus minus} 40 GPA respectively. In addition, the hardness and modulus of Al2O3 were determined to be respectively 10-11 {plus minus} 2 GPA and 200 {plus minus} 40 GPA. |
| Address: | Old Dominion University University of Wisconsin-Madison Old Dominion Unviversity- Applied Research Center |
| LINK | Shim, J.H.; Chao, C.-C.; Huang, H.; Prinz, F.B. |
| "Atomic Layer Deposition of Yttria-Stabilized Zirconia for Solid Oxide Fuel Cells" | |
| Chem. Mater., 2007, 19, 3850-3854 | |
| Abstract: | Abstract: Yttria-stabilized zirconia (YSZ) films were synthesized by atomic layer deposition (ALD). Tetrakis(dimethylamido)zirconium and tris(methylcyclopentadienyl)yttrium were used as ALD precursors with distilled water as oxidant. From X-ray photoelectron spectroscopy (XPS) compositional analysis, the yttria content was identified to increase proportionally to the pulse ratio of Y/Zr. Accordingly, the target stoichiometry ZrO2/Y2O3 = 0.92:0.08 was achieved. Crystal and grain structures of ALD YSZ films grown on amorphous Si3N4 were analyzed by X-ray diffraction (XRD) and atomic force microscopy (AFM). The microstructure of the polycrystalline films consisted of grains of tens of nanometers in diameter. To evaluate ALD YSZ films as oxide ion conductor, freestanding 60 nm films were prepared with porous platinum electrodes on both sides of the electrolyte. This structure served as a solid oxide fuel cell designed to operate at low temperatures. Maximum power densities of 28 mW/cm2, 66 mW/cm2, and 270 mW/cm2 were observed at 265 C, 300 C, and 350 C, respectively. The high performance of thin film ALD electrolyte fuel cells is related to low electrolyte resistance and fast electrode kinetics. The exchange current density at the electrode-electrolyte interface was approximately 4 orders of magnitude higher compared to reference Pt-YSZ values. |
| Address: | Department of Mechanical Engineering and Department of Material Science and Engineering, Stanford University, Stanford, California 94305 |
Showing customer papers 1-10 of 39 Next