Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K77/00—Constructional details of devices covered by this subclass and not covered by groups H10K10/80, H10K30/80, H10K50/80 or H10K59/80
  • H10K77/10—Substrates, e.g. flexible substrates
  • H10K77/111—Flexible substrates
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K50/00—Organic light-emitting devices
  • H10K50/80—Constructional details
  • H10K50/84—Passivation; Containers; Encapsulations
  • H10K50/844—Encapsulations
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K50/00—Organic light-emitting devices
  • H10K50/80—Constructional details
  • H10K50/84—Passivation; Containers; Encapsulations
  • H10K50/844—Encapsulations
  • H10K50/8445—Encapsulations multilayered coatings having a repetitive structure, e.g. having multiple organic-inorganic bilayers
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
  • H10K59/80—Constructional details
  • H10K59/87—Passivation; Containers; Encapsulations
  • H10K59/873—Encapsulations
  • H10K59/8731—Encapsulations multilayered coatings having a repetitive structure, e.g. having multiple organic-inorganic bilayers
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/50—Photovoltaic [PV] energy
  • Y02E10/549—Organic PV cells
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
  • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S428/00—Stock material or miscellaneous articles
  • Y10S428/917—Electroluminescent
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/32—Composite [nonstructural laminate] of inorganic material having metal-compound-containing layer and having defined magnetic layer
  • Y10T428/325—Magnetic layer next to second metal compound-containing layer

Definitions

• a (solid state) ultra high diffusion barrier and encapsulation layer for optoelectronic devices consisting of multiple inorganic layers, which are deposited by a single step vacuum deposition process.
• the present invention relates generally to optoelectronic devices and more specifically to environmentally sensitive optoelectronic devices.
• These devices include organic optoelectronic devices such as organic light emitting diodes (OLED) be it either small molecules or polymer type, organic photovoltaic devices, organic thin film transistors, and organic electrochromic displays, electrophoretic inks, solar devices, and LCD's in general (including applications for watches, cell phones etc.).
• OLED organic light emitting diodes
• Thin polymeric substrates and organic structures have a diffusion coefficient for oxygen and for water, which is far to high to protect the enclosed structures from degradation.
• Thin polymeric substrates and organic structures are susceptible to degradation, deformation and building up of thermally induced stresses when the functional layers are deposited due to the process temperature created intentionally or unintentionally during the deposition.
• figure 1 shows the typical build up for an organic optoelectronic device on an organic substrate: in order to protect the device (here an OLED pixel with its electrodes) from the environment, a barrier layer between the polymeric substrate and the device, and an encapsulation layer covering the whole device are necessary.
• Figure 1 shows a cross section of an OLED device, with an flexible substrate 1, a barrier layer 2, a transparent conductive oxide (TCO) layer 3, OLED layer(s) 4 (organic), cathode 5 and encapsulation layer 6
• TCO transparent conductive oxide
• OLED layer(s) 4 organic
• cathode 5 encapsulation layer 6
• the organic layers 4 and also the metallic cathode 6 need to be protected from oxygen and vapor diffusion, the market requires that the device to be light weight and flexible, the functional layers to be transparent for light of the desired wavelength, the device to be easily manufacturable and the functional layers to have excellent mechanical properties.
• the encapsulation layer 6 needs to offer some mechanical and chemical stability, must seal off the device hermetically and must closely fill the complex top structure of the device during application of the film (step coverage).
• Encapsulation layers have been proposed previously as a combination of a sputtered inorganic layer such as AlO x , SiN, SiON plus a polymer plus another inorganic layer (I-P-I stucture).
• a stack a sequence of I-P-I-P-I... layers have been proposed to further improve the properties of the encapsulation layer (system).
• the inorganic layer prevents the water diffusion while the organic layer have the pupose to planarize the inorganic layer and to provide a new smooth surface to deposit for the next inorganic layer. Pinhole-, particle-, and step coverage are further important functions of the organic layer.
• a coating system suitable for such applications must show several, independent, separable process chambers. Besides the disadvantage of being costly for mass production due to the low throughput, there is also the risk for contamination during the transferring process from (process-) chamber to chamber for the stack formation.
• Figure 1 shows the typical build up for an organic optoelectronic device on an organic substrate, comprising several layers (Order from bottom to top: flexible substrate, barrier layer, TCO (transparent conductive oxide) layer, OLED (organic layers), cathode, and on top: encapsulation layer)
• Figure 2 shows the H 0 permeation rate in grams per day and square meter at 25 degrees Celsius for certain specifications for OPV (organic photo voltaic) and OLED applications and on the same scale typical permeation rates for certain state-of-the-art coatings.
• Figure 3 shows a further embodiment of the invention.
• Figure 4 shows a scanning electron micrograph (SEM) with the excellent step coverage of an inorganic layer according to the invention.
• the present invention provides a diffusion barrier 2 and an encapsulation layer 6 by depositing a set of multiple inorganic layers (preferably of silicon nitride, SiNx) in a single step vacuum deposition process.
• a set of multiple inorganic layers preferably of silicon nitride, SiNx
• FIG. 3 summarizes one embodiment of the present invention:
• a flexible substrate 10 shows barrier layer(s) 11.
• a stack of (multiple) inorganic layers 12 has been deposited, however shows, due to the manufacturing process, pinhole defects 13 and particles 14.
• Each layer of layer stack 12 shields against the environment independently and the average diffusion path lengths between defects are increased significantly.
• the solution of the invention is based on multiple inorganic layers (preferably of silicon nitride).
• This plurality of layers is deposited by an essentially single step PECND process (i.e. including only one loading / unloading operation into the process chamber), directly on polymeric substrates (which are known in the art) with hard coatings (which are also known in the art).
• PECND process i.e. including only one loading / unloading operation into the process chamber
• polymeric substrates which are known in the art
• hard coatings which are also known in the art.
• the layers according to the present invention provide faster packaging than prior art and must prevent damage to the device from moisture and oxygen, thereby improving the lifetime of the device.
• Such layers can also serve as "ultra high diffusion barrier" on polymeric substrates to protect the stack from the attack of moisture and gas through the substrate surface.
• the process parameters are adjusted for each application, e.g. encapsulation on the device side and diffusion barrier on the polymeric substrate side or sides.
• conformal and defect-less layers at relatively low process temperature are required to avoid mechanical deformation of the substrate and damage to the temperature sensitive OLED device.
• a diffusion barrier system for a display device comprises a layer system with at least two layers of dielectric material, wherein at least two adjacent layers of that layer system comprise the same material.
• said dielectric material is one of an nitride, oxide, carbide and oxynitride or combinations thereof.
• Said dielectric material may comprise a metal or a semiconductor, and again the metal is one of Al, Cr, Cu, Ge, In, Ir Sb, Sn, Ta, Ti, Zr or combinations thereof.
• the dielectric material comprises silicon nitride or silicon oxynitride (SiO x N y ).
• a display device with such diffusion barrier layer can be based on a substrate chosen from the group of glass, metal, polymer or paper.
• a method for manufacturing such a diffusion barrier system in a single process chamber of a plasma deposition system will have the steps of introducing a substrate to be treated in said process chamber, discretely varying in a controlled manner during deposition at least one of the process parameters in the process chamber gas flow, power, pressure, temperature without completely interrupting such process parameter, such that each variation results in a layer with different properties. Finally the substrate is removed from said process chamber.
• the "Ca test” is a permeation test, which is based on the corrosion of reactive metal films.
• This all-optical method is used to quantify the water transmission rate of substrates provided with high performance diffusion barriers and is known to those skilled in the art.
• a glass plate with a Calcium coating is glued to the test substrate (such as polymeric substrates with or without diffusion barrier layer and possibly also a reference glass substrate). Calcium readily reacts with water and oxygen entering the test substrate and becomes progressively transparent. This leads to a change in the optical transmission of Ca coating, which can be monitored in time.
• the change in the transmission of the cells is then used to quantify effective permeation rates (WVTR).
• WVTR effective permeation rates
• the change in the WVTR is also due to the penetration of water through the "glue” material.
• a reference glass substrate which normally has a WNTR of -lxlO "6 is also tested.
• the test glass showed a WVTR of ⁇ 3xl 0 "5 and relative to the reference, the WVTR of the polymeric substrate/ barrier layer system is measured to 1.5xl0 "4 .
• the multilayer silicon nitride stack deposited at 120°C showed a WVTR of 5.66x10 "4 .
• the deposition temperature has further been lowered to 80°C with promising results.
• silicon nitride (SiN x ) and silicon oxynitride (SiO x N y ) layers are deposited alternatingly on top of each other.
• the preferred number n of inorganic layers according to the invention is at least 2, with a preferred range of 2 - 10. Even more layers may be useful, and can be adjusted according to specific requirements.
• the thickness of each layer can vary between 15-100 nm (the upper limit can be adjusted according to specific requirements).
• the values for x in SiN x range between 0 and 4/3.
• the barrier layers were prepared with different polymeric substrate pre-treatment, such as cleaning in an ultrasonic bath in order to reduce the particle concentration prior to the deposition, since cracks and micro-cracks initiate at microscopic defect sites, thereby, reducing the permeation rate and the mechanical stability.
• the layers according to the invention are transparent in the visible range, which is a requirement for most structures of optoelectronic devices.
• Silicon nitride multilayer barriers are excellent, both from the mechanical and form the processing standpoint. They are able to resist cracking during OLED processing and possess excellent foldability.
• the crack resistance of the layers is decisive, since mechanical failure of the diffusion barriers will directly result in a shortened lifetime of the device.
• the failure onset of the layers according to the invention is equal to approx. 1.5% strain, which enables a minimum achievable curvature radius of approximately 3-4 mm for a 100 ⁇ m thick substrate. Adhesion of the layers to both glass and to polymeric substrates is found to be very high.
• the analysis prove a very high tensile strength (2.5 GPa) and very high interfacial shear strength (230 MPa) for the layers on polymer, indicating that a strong interface is created during plasma deposition of the nitrides.
• the tensile failure of the SiN x is coupled to that of the underlying hard coat.
• the cohesion and adhesion of SiN x on polymeric substrate with and without hard coat layer before and after hydrothermal loading (lh in water at RT) are found to be essentially unchanged.
• FIG. 4 illustrates in a scanning electron micrograph the excellent step coverage of an inorganic layer according to the invention.
• the inorganic layers according to the present invention are generally chemically very stable (unlike the inorganic/organic stacks in prior art), excellent etching resistance is achieved.
• the chemical compatibility of the prior art diffusion barriers with the OLED processing is a matter of concern.
• Alumina of prior art is not resistant against common etching solutions and the adhesion between the organic and inorganic layer fails easily for instance after processing steps (e.g. etching) and after mechanical and thermal cycling. Due to the inherent stack instability, mechanical failure of such stacks is inevitable.

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• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Electroluminescent Light Sources (AREA)
• Laminated Bodies (AREA)
• Chemical Vapour Deposition (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (2)

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• 2005
  • 2005-02-16 WO PCT/CH2005/000088 patent/WO2005081333A2/en not_active Ceased
  • 2005-02-16 CN CN2005800052876A patent/CN1977404B/zh not_active Expired - Fee Related
  • 2005-02-16 EP EP05706511A patent/EP1719192A2/en not_active Withdrawn
  • 2005-02-16 JP JP2006553410A patent/JP2007526601A/ja active Pending
  • 2005-02-18 TW TW094104751A patent/TWI384583B/zh not_active IP Right Cessation
  • 2005-02-18 US US11/061,143 patent/US7492091B2/en not_active Expired - Fee Related
• 2008
  • 2008-12-09 US US12/330,903 patent/US20090087998A1/en not_active Abandoned

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