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AssigneeAixtron SE
InventorsHolger Jurgensen, Gerhard Karl Strauch, Markus Schwambera
Estimating the term…
The invention relates to a method and a device for depositing especially, organic layers. In a heated reactor, a non-gaseous starting material that is stored in a source in the form of a container is transported from said source to a substrate by a carrier gas in gaseous form and is deposited on said substrate. The rate of production of the gaseous starting material by the source is unpredictable due to a heat input that cannot be regulated in a reproducible manner and due to cooling resulting from the carrier gas. The invention therefore provides that the preheated carrier gas washes through the starting material from bottom to top, the starting material being kept essentially isothermal in relation to the carrier gas by the heated container walls.
Method for depositing in particular organic layers, in which, in a heated reactor (1), a non-gaseous starting material (3), which is held in stock in a source (I) formed by a vessel (2), is transported in the gaseous state (5) from the source (I) to a substrate (II) by means of a carrier gas (4), and is then deposited on the substrate (II), characterized in that the preheated (6) carrier gas (4) is flushed from the bottom upwards through the starting material (3), which is kept substantially isothermal with respect to the carrier gas on account of heated (7) vessel walls (13).
Method according to one or more of the preceding claims or in particular according thereto, characterized in that the heat of evaporation is fed to the starting material (3) via the vessel walls (13) and/or via heating rods (15) which project into the starting material (3).
Method according to one or more of the preceding claims or in particular according thereto, characterized in that the carrier gas is already saturated with the gaseous starting material within the bottom third, preferably bottom fifth, of the receiving chamber.
Method according to one or more of the preceding claims or in particular according thereto, characterized in that the vessel (2) is topped up from the top.
Method according to one or more of the preceding claims or in particular according thereto, characterized in that the carrier gas is fed to the vessel at elevated temperature, so that the heat of sublimation is at least partially removed from the carrier gas.
Device for carrying out a method in particular according to one of the preceding claims, having a source (I), which is associated with a heated reactor, in the form of a vessel (2) for receiving a non-gaseous starting material (3), characterized in that the vessel (2) has an inlet (10) and a gas outlet (11), and, between gas inlet (10) and gas outlet (11), a receiving chamber (12) which can be filled with the starting material, and a heating means (6, 7) for substantially isothermal heating of the carrier gas (4) and of the starting material (3) is associated with the vessel walls (13) and the carrier-gas feed lines (14) which open out into the gas inlet (10).
Device according to one of the preceding claims or in particular according thereto, characterized in that the vessel (2) has a gas-permeable partition (16), which is at a spacing from the gas inlet and on which the starting material, which is in particular in powder or granule form, is located.
Device according to one or more of the preceding claims or in particular according thereto, characterized in that the partition (16) is planar or in the shape of a dome or a cone.
Device according to one or more of the preceding claims or in particular according thereto, characterized in that the carrier gas (4) and the vessel (2) are heated by the same heating means (6, 7).
Device according to one or more of the preceding claims or in particular according thereto, characterized by heating rods (15) which project into the receptacle (12).
Device according to one or more of the preceding claims or in particular according thereto, characterized by a storage chamber (17) which is disposed above the receiving chamber (12) and is connected to the receiving chamber (12) via a passage (19) which can be blocked off.
Device according to one or more of the preceding claims or in particular according thereto, characterized in that the partition (16) is heatable and in particular consists of metal.
Device according to one or more of the preceding claims or in particular according thereto, characterized in that the gas outlet (11) has a filter, in particular in the form of a frit.
Device according to one or more of the preceding claims or in particular according thereto, characterized in that the gas inlet (10) is disposed at the base (8), and the gas outlet (11) is disposed at the top (9), or the gas inlet (10) is associated with the cover (9) and the gas outlet (11) is associated with the base (8).
Device according to one or more of the preceding claims or in particular according thereto, characterized by an insert which can be filled with the organic material, can be introduced into the vessel (2) and has a gas-permeable insert wall through which the gas flowing through the vessel can flow.
Dependencies are inferred from the claim text.
From the US filing history. Foreign family members aren’t listed.
Backward citations are indexed for grants only.
Characterised by the process of coating: gas flow assisted PVD deposition
Characterised by the coating material: organic material
On other inorganic substrates: by cathodic sputtering
Means for minimising impurities, e.g. dust, moisture or residual gas, in the reaction chamber: reduction of impurities in the source gas
Term end not estimated
This application is a continuation of pending International Patent Application No. PCT/EP01/10961 filed Sep. 22, 2001, which designates the United States and claims priority of pending German Application No. 100 48 759, filed Sep. 29, 2000.
The invention relates to a method for depositing in particular organic layers, in which, in a heated reactor, a non-gaseous starting material, which is held in stock in a source formed by a vessel, is transported in the gaseous state from the source to a substrate by means of a carrier gas, and is then deposited on the substrate.
These methods are used to produce in particular organic light-emitting diodes (OLEDs). It is referred to as the OVPD (organic vapor phase deposition) process. The starting materials used are organic molecules which are present in particular in the form of salts and in granule form, but may also be in the liquid state. These molecules have a very low vapor pressure. As a result of the starting material being heated, it is converted into the gaseous state by sublimation. In the prior art, the vessel is a dish which is open at the top and which contains the starting material. This dish is pushed into a source zone of the heated reactor. The starting material which evaporates from the bed of granules or a melt is transported through the reactor by means of a carrier gas, for example nitrogen. The substrate may be at a substrate temperature which is lower than the source temperature. The starting material can be deposited there. In the prior art, process pressures of 0.2 mbar are used.
Exemplary embodiments of the invention are explained below with reference to accompanying drawings, in which:
FIG. 1 shows the method or the device for carrying out the method according to the prior art, in highly diagrammatic form,
FIG. 2 shows, likewise only in diagrammatic form, a first exemplary embodiment of a source which is formed in accordance with the invention,
In the OVPD process, the carrier gas 4 is fed to an externally heated reactor 1. In a first hot zone, the source zone 1, a vessel 2 is placed into the reactor, this vessel containing a bed of a starting material. The starting material is sublimed at the source temperature. The gaseous starting material 5 is then transported with the carrier gas 4 to the substrate 11, where it condenses out of the gas phase in order to deposit a layer there.
The devices which are diagrammatically depicted in FIGS. 2 to 5 replace the dish-like vessel 2 of the prior art which is illustrated in FIG. 1.
According to the invention, the vessel 2 is closed. It has a base 8, in particular cylindrical sidewalls 13 and a cover 9. The base has a gas inlet 10. The cover has a gas outlet 11. In the lower region of the vessel 2, which consists of metal, in particular aluminum, there is an inflow space, into which the carrier gas 4, which flows through the carrier-gas feed line 14, can flow. At the top, this space is delimited by a porous partition 16. The gas stream passes through this partition and into the starting material 3 which forms a bed on the partition 16. The carrier gas 4 flushes through the starting material 3 from the bottom upward, the carrier gas being saturated with the gaseous starting material even just above the partition 16 and being discharged into the reactor from the gas outlet 11 together with the gaseous starting material 5. The entire device as illustrated in FIGS. 2 to 5 can be integrated in the reactor. The reactor is structurally adapted.