Showing papers on "Atomic layer deposition published in 2007"

Process for atomic layer deposition

Abstract: The present invention relates to a process of making a zinc-oxide-based thin film semiconductor, for use in a transistor, comprising thin film deposition onto a substrate comprising providing a plurality of gaseous materials comprising at least first, second, and third gaseous materials, wherein the first gaseous material is a zinc-containing volatile material and the second gaseous material is reactive therewith such that when one of the first or second gaseous materials are on the surface of the substrate the other of the first or second gaseous materials will react to deposit a layer of material on the substrate and wherein the third gaseous material is inert with respect to reacting with the first or second gaseous materials.

Synthesis and Surface Engineering of Complex Nanostructures by Atomic Layer Deposition

Abstract: Atomic layer deposition (ALD) has recently become the method of choice for the semiconductor industry to conformally process extremely thin insulating layers (high-k oxides) onto large-area silicon substrates. ALD is also a key technology for the surface modification of complex nanostructured materials. After briefly introducing ALD, this Review will focus on the various aspects of nanomaterials and their processing by ALD, including nanopores, nanowires and -tubes, nanopatterning and nanolaminates as well as low-temperature ALD for organic nanostructures and biomaterials. Finally, selected examples will be given of device applications, illustrating recent innovative approaches of how ALD can be used in nanotechnology.

ZnO Nanotube Based Dye-Sensitized Solar Cells

Abstract: We introduce high surface area ZnO nanotube photoanodes templated by anodic aluminum oxide for use in dye-sensitized solar cells (DSSCs) Atomic layer deposition is utilized to coat pores conformally, providing a direct path for charge collection over tens of micrometers thickness Compared to similar ZnO-based devices, ZnO nanotube cells show exceptional photovoltage and fill factors, in addition to power efficiencies up to 16% The novel fabrication technique provides a facile, metal-oxide general route to well-defined DSSC photoanodes

ZnO-TiO2 Core-Shell Nanorod/P3HT Solar Cells

Abstract: We evaluate an ordered organic−inorganic solar cell architecture based on ZnO−TiO2 core−shell nanorod arrays encased in the hole-conducting polymer P3HT. Thin shells of TiO2 grown on the ZnO nanorods by atomic layer deposition significantly increase the voltage and fill factor relative to devices without shells. We find that the core−shell cells must be exposed to air to reproducibly attain efficiencies higher than 0.05%. Cells stored in air for 1 month are 0.29% efficient.

Excellent passivation of highly doped p-type Si surfaces by the negative-charge-dielectric Al2O3

Abstract: From lifetime measurements, including a direct experimental comparison with thermal SiO2, a-Si:H, and as-deposited a-SiNx:H, it is demonstrated that Al2O3 provides an excellent level of surface passivation on highly B-doped c-Si with doping concentrations around 1019cm−3. The Al2O3 films, synthesized by plasma-assisted atomic layer deposition and with a high fixed negative charge density, limit the emitter saturation current density of B-diffused p+-emitters to ∼10 and ∼30fA∕cm2 on >100 and 54Ω∕sq sheet resistance p+-emitters, respectively. These results demonstrate that highly doped p-type Si surfaces can be passivated as effectively as highly doped n-type surfaces.

Atomic layer deposition of yttria-stabilized zirconia for solid oxide fuel cells

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 d...

Enhanced atomic layer deposition

Abstract: A method of enhanced atomic layer deposition is described. In an embodiment, the enhancement is the use of plasma. Plasma begins prior to flowing a second precursor into the chamber. The second precursor reacts with a prior precursor to deposit a layer on the substrate. In an embodiment, the layer includes at least one element from each of the first and second precursors. In an embodiment, the layer is TaN. In an embodiment, the precursors are TaF 5 and NH 3 . In an embodiment, the plasma begins during the purge gas flow between the pulse of first precursor and the pulse of second precursor. In an embodiment, the enhancement is thermal energy. In an embodiment, the thermal energy is greater than generally accepted for ALD (>300 degrees Celsius). The enhancement assists the reaction of the precursors to deposit a layer on a substrate.

Effective electrical passivation of Ge(100) for high-k gate dielectric layers using germanium oxide

Abstract: In search of a proper passivation for high-k Ge metal-oxide-semiconductor devices, the authors have deposited high-k dielectric layers on GeO2, grown at 350–450°C in O2. ZrO2, HfO2, and Al2O3 were deposited by atomic layer deposition (ALD). GeO2 and ZrO2 or HfO2 intermix during ALD, together with partial reduction of Ge4+. Almost no intermixing or reduction occurs during Al2O3 ALD. Capacitors show well-behaved capacitance-voltage characteristics on both n- and p-Ge, indicating efficient passivation of the Ge∕GeOx interface. The density of interface states is typically in the low to mid-1011cm−2eV−1 range, approaching state-of-the-art Si∕HfO2∕matal gate devices.

Simplified pitch doubling process flow

Abstract: A method for fabricating a semiconductor device comprises patterning a layer of photoresist material to form a plurality of mandrels. The method further comprises depositing an oxide material over the plurality of mandrels by an atomic layer deposition (ALD) process. The method further comprises anisotropically etching the oxide material from exposed horizontal surfaces. The method further comprises selectively etching photoresist material.

Plasma and thermal ALD of Al2O3 in a commercial 200 mm ALD reactor

Abstract: The deposition of Al 2 O 3 by remote plasma atomic layer deposition (ALD) in the Oxford Instruments FlexAL reactor was studied and compared with results from thermal ALD in the same reactor. Trimethylaluminum [Al(CH 3 ) 3 ] was used as the metal precursor and O 2 plasma and H 2 O were used as oxidizing agents for the plasma and thermal processes, respectively. For remote plasma ALD with a total cycle time of 4 s, the growth per cycle decreased monotonically with substrate temperature, from 1.7 A/cycle at 25°C to 1.0 A/cycle at 300°C. This growth per cycle was consistently higher than that obtained for thermal ALD. For the latter a maximum growth per cycle of ∼ 1.0 A/cycle was found at 200°C. The film properties investigated were nearly independent of oxidant source for temperatures between 100 and 300°C, with a slightly higher mass density for the remote plasma ALD Al 2 O 3 films. Films deposited at 200 and 300°C were stoichiometric with a mass density of 3.0 g/cm 3 and low C (< 1 atom %) and H (<3 atom %) contents. At lower substrate temperatures, oxygen-rich films were obtained with a lower mass density and higher H-content. Remote plasma ALD produced uniform Al 2 O 3 films with nonuniformities of less than ±2% over 200 mm diam substrates. Excellent conformality was obtained for films deposited in macropores with an aspect ratio of ∼8 (2.0-2.5 μm diam). Preliminary results on electrical properties of remote plasma deposited films showed high dielectric constants of 7.8 and 8.9 for as-deposited and forming gas annealed Al 2 O 3 , respectively.

Ordered Iron Oxide Nanotube Arrays of Controlled Geometry and Tunable Magnetism by Atomic Layer Deposition

Abstract: Iron oxide nanotubes of 50−150 nm outer diameter and 2−20 nm wall thickness are prepared in ordered arrays. Atomic layer deposition (ALD) of Fe2O3 from the precursor iron(III) tert-butoxide at 130−180 °C yields very smooth coverage of the pore walls of anodic alumina templates, with thickness growth of 0.26(±0.04) A per cycle. The reduced Fe3O4 tubes are hard ferromagnets, and variations of the wall thickness dw have marked consequences on the magnetic response of the tube arrays. For 50 nm outer diameter, tubes of dw = 13 nm yield the largest coercive field (Hc > 750 Oe), whereas lower coercivities are observed on both the thinner and thicker sides of this optimum.

Solid precursor-based delivery of fluid utilizing controlled solids morphology

Abstract: Apparatus and method for volatilizing a source reagent susceptible to particle generation or presence of particles in the corresponding source reagent vapor, in which such particle generation or presence is suppressed by structural or processing features of the vapor generation system. Such apparatus and method are applicable to liquid and solid source reagents, particularly solid source reagents such as metal halides, e.g., hafnium chloride. The source reagent in one specific implementation is constituted by a porous monolithic bulk form of the source reagent material. The apparatus and method of the invention are usefully employed to provide source reagent vapor for applications such as atomic layer deposition (ALD) and ion implantation.

Atomic layer deposition of TiO2 from tetrakis-dimethyl-amido titanium or Ti isopropoxide precursors and H2O

Abstract: Atomic layer deposition (ALD) of TiO2 thin films using Ti isopropoxide and tetrakis-dimethyl-amido titanium (TDMAT) as two kinds of Ti precursors and water as another reactant was investigated. TiO2 films with high purity can be grown in a self-limited ALD growth mode by using either Ti isopropoxide or TDMAT as Ti precursors. Different growth behaviors as a function of deposition temperature were observed. A typical growth rate curve-increased growth rate per cycle (GPC) with increasing temperatures was observed for the TiO2 film deposited by Ti isopropoxide and H2O, while surprisingly high GPC was observed at low temperatures for the TiO2 film deposited by TDMAT and H2O. An energetic model was proposed to explain the different growth behaviors with different precursors. Density functional theory (DFT) calculation was made. The GPC in the low temperature region is determined by the reaction energy barrier. From the experimental results and DFT calculation, we found that the intermediate product stability ...

PEALD Deposition of a Silicon-Based Material

Abstract: A process for depositing a silicon-based material on a substrate uses the technology of plasma-enhanced atomic layer deposition. The process is carried out over several cycles, wherein each cycle includes: exposing the substrate to a first precursor, which is an organometallic silicon precursor; and applying a plasma of at least a second precursor, different from the first precursor. Semiconductor products such as 3D capacitors, vertical transistor gate spacers, and conformal transistor stressors are made from the process.

Method of Forming A Metallic Oxide Film Using Atomic Layer Deposition

Abstract: A method of forming a metallic oxide film using atomic layer deposition includes loading a substrate into a reactor, supplying a metallic source gas into the reactor and absorbing the metallic source gas onto the substrate, purging the remaining metallic source gas that does not react, with the substrate, and directly producing plasma of an N-group-containing oxide reactant gas in the reactor.

Method for depositing thin films by mixed pulsed CVD and ALD

Abstract: Films are deposited on a substrate by a process in which atomic layer deposition (ALD) is used to deposit one layer of the film and pulsed chemical vapor deposition (CVD) is used to deposit another layer of the film. During the ALD part of the process, a layer is formed by flowing sequential and alternating pulses of mutually reactive reactants that deposit self-limitingly on a substrate. During the pulsed CVD part of the process, another layer is deposited by flowing two CVD reactants into a reaction chamber, with at least a first of the CVD reactants flowed into the reaction chamber in pulses, with those pulses overlapping at least partially with the flow of a second of the CVD reactants. The ALD and CVD parts of the process ca be used to deposit layers with different compositions, thereby forming, e.g., nanolaminate films. Preferably, high quality layers are formed by flowing the second CVD reactant into the reaction chamber for a longer total duration than the first CVD reactant. In some embodiments, the pulses of the third reactant at separated by a duration at least about 1.75 times the length of the pulse. Preferably, less than about 8 monolayers of material are deposited per pulse of the first CVD reactant.

Method and apparatus for atomic layer deposition using an atmospheric pressure glow discharge plasma

Abstract: Apparatus and method for atomic layer deposition on a surface of a substrate (6) in a treatment space. A gas supply device (15, 16) is present for providing various gas mixtures to the treatment space. The gas supply device (15, 16) is arranged to provide a gas mixture with a precursor material to the treatment space for allowing reactive surface sites to react with precursor material molecules to give a surface covered by a monolayer of precursor molecules attached via the reactive sites to the surface of the substrate. Subsequently, a gas mixture comprising a reactive agent capable to convert the attached precursor molecules to active precursor sites is provided. A plasma generator (10) is present for generating an atmospheric pressure plasma in the gas mixture comprising the reactive agent.

Apparatus for atomic layer deposition

Abstract: The present invention provides a distribution manifold (10) for thin-film material deposition onto a substrate (20) comprising a plurality of inlet ports (18) for a sequence of gaseous materials, an output face comprising a plurality of open elongated output channels (12), each channel extending in a length direction substantially in parallel. The distribution manifold (10) can be employed in a deposition system for thin film deposition, further comprising a plurality of sources for a plurality of gaseous materials and a support for positioning a substrate in pre-designed close proximity to the output face of the distribution manifold (10). During operation of the system, relative movement between the output face and the substrate support is accomplished.

Method of eliminating a lithography operation

Abstract: Methods of semiconductor device fabrication are disclosed. An exemplary method includes processes of depositing a first pattern on a semiconductor substrate, wherein the first pattern defines wide and narrow spaces; depositing spacer material over the first pattern on the substrate; etching the spacer material such that the spacer material is removed from horizontal surfaces of the substrate and the first pattern but remains adjacent to vertical surfaces of a wide space defined by the first pattern and remains within narrow a space defined by the first pattern; and removing the first pattern from the substrate. In one embodiment, the first pattern can comprise sacrificial material, which can include, for example, polysilicon material. The deposition can comprise physical vapor deposition, chemical vapor deposition, electrochemical deposition, molecular beam epitaxy, atomic layer deposition or other deposition techniques. According to another embodiment, features for lines and logic device components having a width greater than that of the lines are formed in the spacer material in the same mask layer.

Atomic layer deposition on particles using a fluidized bed reactor with in situ mass spectrometry

Abstract: A fluidized bed reactor (FBR) was designed and constructed for the delivery of reactive gases to particle surfaces to functionalize particles at large scale using atomic layer deposition (ALD). Nano- and micron-sized particles were effectively fluidized using an inert carrier gas assisted by mechanical agitation of the powder bed. The gas-solid contacting properties of fluidized bed reactors are beneficial for ALD surface reactions, while the frequent solid-solid collisions do not disrupt the self-limiting behavior of ALD reactant gases. Films can be deposited with monolayer control on individual particles of various substrate types, including metals, ceramics and polymers. In situ mass spectrometry was used for real-time monitoring of gaseous product(s) and reactants throughout the ALD reaction. Alumina (Al 2 O 3 ) ALD on particles demonstrates the process control capabilities of this unique, scalable configuration. The applications of Al 2 O 3 ALD films on particles are widely varying but typically involve core substrate surface passivation, which includes thermal oxidation resistance, photocatalytic activity mitigation and the fabrication of electrically insulative metal particles. Particle functionalization is achievable to nanoscale precision on a wide range of substrate types and sizes with minimal waste of costly ALD precursors and process time.

Atomic layer deposition on electrospun polymer fibers as a direct route to AL2O3 microtubes with precise wall thickness control.

Abstract: Atomic layer deposition (ALD) of Al2O3 on electrospun poly(vinyl alcohol) microfiber templates is demonstrated as an effective and robust strategy by which to fabricate long and uniform metal-oxide microtubes. The wall thickness is shown to be precisely controlled within a molecular layer or so by adjusting the number of ALD cycles utilized. By judicious selection of the electrospinning and ALD parameters, designer tubes of various sizes and inorganic materials can be synthesized.

Submicrometer Inversion-Type Enhancement-Mode InGaAs MOSFET With Atomic-Layer-Deposited $\hbox{Al}_{2}\hbox{O}_{3}$ as Gate Dielectric

Abstract: High-performance inversion-type enhancement-mode n-channel In053Ga047As MOSFETs with atomic-layer-deposited (ALD) Al2O3 as gate dielectric are demonstrated The ALD process on III-V compound semiconductors enables the formation of high-quality gate oxides and unpinning of Fermi level on compound semiconductors in general A 05-mum gate-length MOSFET with an Al2O3 gate oxide thickness of 8 nm shows a gate leakage current less than 10-4 A/cm2 at 3-V gate bias, a threshold voltage of 025 V, a maximum drain current of 367 mA/mm, and a transconductance of 130 mS/mm at drain voltage of 2 V The midgap interface trap density of regrown Al2O3 on In053Ga047As is ~14 x 1012/cm2 ldr eV which is determined by low-and high-frequency capacitance-voltage method The peak effective mobility is ~1100 cm2 / V ldr s from dc measurement, ~2200 cm2/ V ldr s after interface trap correction, and with about a factor of two to three higher than Si universal mobility in the range of 05-10-MV/cm effective electric field

Periodic plasma annealing in an ALD-type process

Abstract: Methods for performing periodic plasma annealing during atomic layer deposition are provided along with structures produced by such methods. The methods include contacting a substrate with a vapor-phase pulse of a metal source chemical and one or more plasma-excited reducing species for a period of time. Periodically, the substrate is contacted with a vapor phase pulse of one or more plasma-excited reducing species for a longer period of time. The steps are repeated until a metal thin film of a desired thickness is formed over the substrate.

Method of forming crystallographically stabilized doped hafnium zirconium based films

Abstract: A method is provided for forming doped hafnium zirconium based films by atomic layer deposition (ALD) or plasma enhanced ALD (PEALD). The method includes disposing a substrate in a process chamber and exposing the substrate to a gas pulse containing a hafnium precursor, a gas pulse containing a zirconium precursor, and a gas pulse containing one or more dopant elements. The dopant elements may be selected from Group II, Group XIII, silicon, and rare earth elements of the Periodic Table. Sequentially after each precursor and dopant gas pulse, the substrate is exposed to a gas pulse containing an oxygen-containing gas, a nitrogen-containing gas, or an oxygen- and nitrogen-containing gas. In alternative embodiments, the hafnium and zirconium precursors may be pulsed together, and either or both may be pulsed with the dopant elements. The sequential exposing steps may be repeated to deposit a doped hafnium zirconium based film with a predetermined thickness.

Method of depositing nanolaminate film for non-volatile floating gate memory devices by atomic layer deposition

Abstract: Disclosed herein is a method of depositing a nanolaminate film for next-generation non-volatile floating gate memory devices by atomic layer deposition. The method includes the steps of: introducing a substrate into an atomic layer deposition reactor; forming on the substrate a first high-dielectric-constant layer by alternately supplying an oxygen source and a metal source selected from among an aluminum source, a zirconium source and a hafnium source; forming on the first high-dielectric-constant layer a nickel oxide layer by alternately supplying a nickel source and an oxygen source; and forming on the nickel oxide layer a second high-dielectric-constant layer by alternately supplying an oxygen source and a metal source selected from among an aluminum source, a zirconium source and a hafnium source. The nanolaminate film deposited according to the method shows good memory window characteristics compared to those of memory devices fabricated using nanocrystal floating gates according to the prior physical vapor deposition methods, and thus can be applied to non-volatile floating gate memory devices.

Method of manufacturing semiconductor device

Abstract: The invention aims at enabling leakage current characteristics and a step coverage property to be improved by depositing a hafnium silicate film by utilizing an atomic layer evaporation method using a hafnium raw material, a silicon raw material and an oxidizing agent Disclosed herein is a method of manufacturing a semiconductor device having a trench capacitor including a first electrode formed on an inner surface of a trench, a capacitor insulating film formed on a surface of the first electrode, and a second electrode formed on a surface of the capacitor insulating film The method includes the step of depositing the capacitor insulating film in a form of a hafnium silicate film by utilizing an atomic layer deposition method using a hafnium raw material, a silicon raw material and an oxidizing agent

Ferromagnetic nanotubes by atomic layer deposition in anodic alumina membranes

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 O3. 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 35to60nm exhibit a preferential magnetization direction along the nanowire axis. The Ni or Co nanotubes with larger diameters (around 160nm) show a nearly isotropic magnetic behavior, with the magnetic moments arranged in a vortex state at zero field.

Manufacturing method of semiconductor integrated circuit

Abstract: An object of the present invention is to provide a method of depositing yttrium-stabilized hafnia use for a DRAM capacitor insulating film while controlling the composition at a high accuracy by an atomic layer deposition method. The atomic deposition method is performed by introducing a hafnium compound precursor, introducing a yttrium compound precursor and introducing an oxidant as one cycle. In the atomic deposition method, the addition amount of yttrium into hafnia is controlled accurately by controlling the time of introducing the hafnium compound precursor and the yttrium compound precursor and controlling the replacement ratio of OH groups on a sample surface by each of the precursors.

High performance thin film transistor with low temperature atomic layer deposition nitrogen-doped ZnO

Abstract: High performance thin film transistor (TFT) with atomic layer deposition (ALD) nitrogen doped ZnO (ZnO:N) as an active layer is demonstrated The electrical properties of ZnO thin films were effectively controlled by in situ nitrogen doping using NH4OH as a source for reactants Especially, the electron concentration in ZnO was lowered to below 1015cm−3 Good device characteristics were obtained from the inverted staggered type TFTs with ZnO:N channel and ALD Al2O3 gate insulator; μsat=67cm2∕Vs, Ioff=203×10−12A, Ion∕off=946×107, and subthreshold swing=067V∕decade The entire TFT fabrication processes were carried out at below 150°C, which is a favorable process for plastic based flexible display

Shallow trench isolation using atomic layer deposition during fabrication of a semiconductor device

Abstract: A method for providing an isolation material, for example trench isolation for a semiconductor device, comprises forming a first dielectric such as silicon dioxide using an atomic layer deposition (ALD) process within a trench, partially etching the first dielectric, then forming a second dielectric such as a silicon dioxide using a high density plasma (HDP) deposition within the trench. The second dielectric provides desirable properties such as resistance to specific etches than the first dielectric, while the first dielectric fills high aspect ratio openings more easily than the second dielectric. Depositing the first dielectric results in a decreased trench aspect ratio which must be filled by the second dielectric.