DE102007023803B4 - Process for the production of layer systems with intermediate layers and article with layer system with intermediate layers - Google Patents

Abstract

A process for the production of layer systems in which a layer system with at least two layers is applied to an object and at least one intermediate layer is introduced between the layers and wherein for the application of the intermediate layer an organic precursor and an inorganic precursor simultaneously or successively in the coating or Reaction chamber are introduced and the organic precursor and the inorganic precursor are brought substantially simultaneously to the reaction and / or deposition and the intermediate layer is deposited in a thickness of 3 nm to 10 nm.

Description

The This invention relates generally to methods for making layer systems with intermediate layers and a preferably prepared according to the method Object with at least one layer system, which one or contains several intermediate layers.

interlayers in conventional Layer systems have already been used to study the morphology of the To influence shift system.

In the WO 2004 026786 A1 describes methods and arrangements for the production of protective layers in which a protective layer for a body comprising at least one hard material layer of a metal oxide and / or metal nitride and / or metal carbide and / or metal oxonitride and / or metal carbonitride and / or metal oxocarbonitride, on a body is applied and in which this protective layer comprises a functional layer which is interrupted by at least one, different from the functional layer intermediate layer of a metal oxide and / or metal nitride and / or metal carbide and / or metal oxonitride and / or metal carbonitride and / or metal oxocarbonitride and the intermediate layer a in relation to the functional layer is very thin layer, wherein the intermediate layer interrupts the morphology of the functional layer.

The WO 2004/026787 A1 describes a method for the production of layers and layer systems as well as a coated substrate produced according to the method, wherein in the method at least one functional layer is applied, and this providing the substrate and the layer starting material in a vacuum system and the coating of the substrate with a functional layer by means of sputtering of the layer starting material and sputtering the layer source material to coat the substrate, and interrupting the functional layer at least once, and producing an intermediate layer other than the functional layer, the thickness of which is ≤ 20 nm and the sputtering of the layer source material is continued after the interruption.

WO 2004/026785 A1 comprises a coated article having at least one functional layer, wherein in at least one functional layer at least one intermediate layer, the intermediate layer has a layer thickness of d _z ≤ 10 nm, and the intermediate layer interrupts the morphology of the functional layer.

The However, the interlayers described above are known in the art Layer systems introduced so that each one layer of this Interrupt layer system, this means between two at least be arranged from the material identical layers.

The DE 3 941 859 C1 teaches to adjust the refractive index of optical layers in an interference-optical layer system to use a mixture of SiO ₂ and TiO ₂ . Depending on the mixing ratio, refractive indices between that of TiO ₂ (about 2.5) and that of SiO ₂ (about 1.5) are possible:
Frequently, alternating optical layer systems with alternating high and low refractive index layers are used to produce coatings for cold light reflectors. These coating systems are partially applied by PICVD methods.

From none of the intermediate layers was an influence on the electrical conductivity of Layer systems known. Furthermore, these layer systems were created by alternately an organic precursor and an inorganic Precursor was used for coating. The simultaneous use an organic precursor and an inorganic precursor has hitherto been strictly avoided in these coatings, to avoid chemical reactions, some of which are undesirable Contamination of piping systems and reaction chambers.

In important applications such layer systems, the electrical conductivity play a significant role.

Reflectors for digital projection usually incorporate high intensity gas discharge lamps. These lamps are ignited with a voltage of several 1000 V. The power lines are partially guided through holes in the reflector and have, as far as these lines in the region of the reflector, as usual not carried out in isolation, contact with the layer system, conductive layer systems then cause problems. The ignition voltage can be short-circuited by a conductive layer system, which prevents ignition of the lamp. The flange of several reflectors has built in th state contact with metal parts. The ignition voltage can be dissipated through these parts and damage other components or put housing parts under voltage.

Of the Invention is based on the object, a layer system with reduced electrical conductivity and a method for producing layer systems with reduced electrical conductivity provide.

Especially would be advantageous it, if already existing layer systems essentially without change of the Schichtdesings can be maintained. These tasks will be with a method having the features of claim 1 and a An article with the features of claim 12 solved.

conventional Layer system have, for example, in interference-optical alternating-layer systems, Thicknesses of the applied layers of about 10 nm to 200 nm. Surprisingly The inventors have found that the incorporation of thin intermediate layers in one or more of these interference optical alternating layers a serious reduction in the conductivity of this layer system had the consequence.

When thin intermediate layer was thereby a layer with thicknesses of about 3 nm to 10 nm and preferably introduced from 4 nm to 6 nm.

Surprisingly the inventors have further found that these intermediate layers only then the conductivity reduced when an organic precursor and an inorganic Precursor simultaneously in the coating or reaction chamber and simultaneously for reaction and / or separation were brought.

Further it was also surprising that these intermediate layers the electrical conductivity then particularly greatly reduced, if this between two layers were introduced with different material composition.

Alternating shift systems with such intermediate layers have depending on manufacturing parameters a reduced to greatly reduced electrical conductivity. With 5000 V measurement voltage in layer systems according to the invention electrical resistors in the high GΩ range or TΩ range measured. Whereas, the same layer system without intermediate layers at a measuring voltage of 5000 V a lower resistance down to in the kΩ range can own.

The Invention will be described below with reference to preferred embodiments and with reference to the accompanying figures in more detail described.

It demonstrate:

1 schematic representation of a layer system with mixed intermediate layers, which are incorporated in a conventional interference optical cold light mirror layer system,

2 Results of conductivity measurements, which reflect the influence of the mixed intermediate layers on the electrical resistance of oxide layer systems.

Detailed description more preferred embodiments

at the preferred embodiments described in more detail below were interference-optical alternating-layer systems on glass and glass ceramic reflectors applied, which conventional layer designs had, in which introduced to reduce the conductivity intermediate layers were.

These Intermediate layers are also referred to as mixed intermediate layers, as far as thereby for their production both organic and inorganic Precursors used at the same time or in particular as a mixture become.

The conventional layer system comprises multiple layers of SiO _x C _y and TiO _x Cl _y layers. The layer systems consist of TiO _x Cl _y and SiO _x C _y layers of specific thickness and form an interference layer system with a defined spectrum.

The TiO _x Cl _y layers are made from a blend of TiCl ₄ and O _2, and usually contain chlorine nor residues.

The SiO _x C _y layers are prepared from HMDSO-oxygen mixture ((CH ₃ ) ₃ -Si-O-Si (CH ₃ ) ₃ ) and contain carbon and hydrogen radicals.

The SiO _x C _y layers alone usually have almost no conductivity.

The TiO _x Cl _y layers have as a single layer only a low conductivity.

It is the combination of SiO _x C _y - and TiO _x Cl _y layers in the layer system led to the observed high conductivity of the layer systems. The mechanism by which this conductivity is induced is currently unknown.

Surprisingly, the inventors have found that thin mixed layers interposed between the SiO _x C _y and TiO _x Cl _y layers can significantly reduce the conductivity of the alternating layer systems.

These are preferably prepared by simultaneously passing HMDSO, TiCl ₄ and O ₂ into the reactor.

The Coating time for these mixed intermediate layers is between one tenth and several seconds, for example ten seconds, preferably about one second.

The conductivity reduction by this measure works with both glass reflectors and glass-ceramic reflectors.

Mixed intermediate layers which are produced only from inorganic precursors, for example from SiCl ₄ and TiCl ₄ and O ₂ , show no reduction in conductivity.

Surprisingly leads the Combination of an organic and an inorganic precursor, however to a significant reduction in conductivity.

Mixed intermediate layers, which are interposed between the SiO _x C _y and TiO _x Cl _y layers of an oxide layer system, reduce the electrical conductivity of this layer system.

These intermediate layers are advantageously produced for example with a gas mixture of TiCl ₄ , HMDSO and O ₂ .

apparently it is necessary an organic with an inorganic precursor to mix to a conductivity reducing Effect.

Therefore, the conductivity reduction can not be done solely by forming a SiO ₂ -TiO ₂ mixed layer. There must be an interaction of other precursor constituents. In addition to silicon and oxygen, the HMDSO molecule also contains organic components, namely carbon and hydrogen, which appear to be essential for reducing the conductivity.

embodiment 1: Effect of the mixed layers on the laboratory system.

One ellipsoidal glass-ceramic reflector with a height of about 5 cm and a maximum Diameter of about 5 cm was for the following Trials used.

The coating of the test reflectors was done with a cold light mirror consisting of 15 layers TiO _x Cl _y , and 16 layers SiO _x C _y . For the deposition of these layers, a plasma CVD method was used in which the plasma is generated by a pulsed microwave field (PICVD method). The pulse power for the SiO _x C _y layers was 3000 W and for the TiO _x Cl _y layers 2800 W.

It was for both layers have a duty cycle of 0.02, where the duty cycle is the temporal relationship between existing microwave radiation and switched off microwave irradiation describes.

Of the Pressure in the coating chamber was about 0.5 mbar.

Of the Inflow of the coating gases and the exhaust of the exhaust gases took place continuously.

The SiO _x C _y layers were produced using a gas mixture of about 97% by volume O ₂ and 3% by volume hexamethylene disiloxane (HMDSO).

The TiO _x Cl _y layers were prepared with a mixture of about 0.5 vol.% And 2 vol.% TiCl ₄ in O ₂ , respectively.

The gas for the deposition of the mixed intermediate layers consisted of 3 vol.% HMDSO, 0.5 vol.% And 2 vol.% TiCl ₄ and 96.5 vol.% And 95 vol.% O, respectively ₂ .

Of the Pressure was 0.5 mbar, the pulse power 3000 W, the duty cycle 0.02. In this example, the coating time for the mixed intermediate layers varied. First Some reflectors without mixed intermediate layers were produced and measured.

These showed after annealing at 450 ° C for 20 min increased conductivity (or low resistance).

The Resistance measurement was carried out at various points on the reflector surface about 1000 V and an electrode spacing of the measuring electrodes of about 5 mm.

It could resist this down to the single-digit MΩ range be measured.

With increasing coating time for the mixed intermediate layers the sheet resistance increased. At one second coating time became after annealing at all measuring points on the reflector surface Resistance of> 2 GΩ measured, which corresponds to the measuring range end value of the measuring device used.

embodiment 2: Effect of mixed layers in production

The Concept of mixed intermediate layers shown on a laboratory plant was transferred to a production plant and tested.

The test object was an ellipsoidal glass reflector with a height of approx. 6 cm and a maximum diameter of approx. 5.5 cm. The same layer system was applied to this reflector as in Example 1, but with different coating parameters: SiO _x C _y layers: Pulse power: 8000 W duty cycle: 0.028 HMDSO conc .: 2.7% by volume TiO _x Cl _y layers: Pulse power: 6000 W Duty cycle: 0,028 TiCl ₄ concentration: 1.1% by volume Mixed interlayers: Pulse power: 6000 or 8000 W duty cycle: 0.028 HMDSO conc .: 2.7% by volume TiCl ₄ : 1.1% by volume Coating time: 1 s

With these parameters layer systems without and with mixed intermediate were used on the same system layers produced.

To the annealing of the samples was carried out measuring the electrical conductivity. For each reflector, the electrical resistance between different measure precisely defined points. The measuring voltage was 5000 V. The full scale value of the meter is 1 TΩ.

In 2 the results of the conductivity measurements on the layer systems described above are summarized.

These Results of conductivity measurements, which in each case the influence of the mixed intermediate layers on the reflect electrical resistance of oxide layer systems, each show the same layer system, which at different points on the surface was measured. The left higher Bars show the electrical resistance of a coating system without Interlayers and the right bars are essentially the same Layer system, but without introduced intermediate layers. One sees, that the electrical conductivity of the layer system through the intermediate layers at some measuring positions could be reduced significantly.

The Layer systems with mixed intermediate layers have many measuring positions one by about 6 orders of magnitude higher electrical resistance.

This clearly shows that the inventive conductivity reduction in industrial Production equipment is applicable.

The invention is also applied to those in the in WO 2004/026786 A1 . WO 2004/026782 A1 . WO 2004/026787 A1 and WO 2004/026785 A1 described method and the objects produced therein according to the method extended and it is the content of WO 2004/026786 A1 . WO 2004/026782 A1 . WO 2004/026787 A1 as well as the WO 2004/026785 A1 by reference also to the subject matter of the present specification and the present application.

Claims (14)

Process for the production of layer systems, in which on a subject a layer system with at least two layers is applied and at least one intermediate layer is introduced between the layers and in which to apply the intermediate layer is an organic precursor and an inorganic precursor Precursor simultaneously or sequentially in the coating or Reaction chamber are introduced and the organic precursor and the inorganic precursor substantially simultaneously to the reaction and / or deposition and the intermediate layer in a thickness of 3 nm to 10 nm is deposited. Process for the preparation of layer systems according to Claim 1, wherein the organic precursor hexamethylene disiloxane (HMDSO) and / or tetramethyldisiloxane (TMDSO), tetraethylorthosilicate (TEOS), tetramethylcyclotetrasiloxane (TMCTSO). Process for the preparation of layer systems according to Claim 1 or 2, in which the inorganic precursor comprises TiCl ₄ and / or NbCl ₅ , TaCl ₃ , ZrCl ₄ . A method of making layer systems according to claim 1, 2 or 3, wherein the layers comprise at least one SiO _x C _y layer in which x is from 1.8 to 2.1 and y is <0.05, and at least one TiO _x Cl _y layer in which x is from 1.8 to 2.1 and y <0.02. Process for the production of layer systems according to one of the preceding claims, wherein for the composition of the intermediate layer a deposit comprising 0.5 to 10% by volume HMDSO, preferably 3% by volume HMDSO, 0.2 to 5% by volume TiCl ₄ , preferably 0.5 vol .-% to 2 vol .-% TiCl ₄ and 85 to 99.3 vol .-% O ₂ is used. Process for the production of layer systems according to one of the preceding claims, in which TiO ₂ layers and SiO ₂ layers are deposited alternately for the layer system and preferably the TiO ₂ layers of a mixture of TiCl ₄ and O ₂ and the SiO ₂ layers be deposited from an HMDSO-oxygen mixture. Process for the preparation of layer systems according to one of the preceding claims, in which the introduction and mixing of the organic and inorganic precursor in a feed before the coating chamber he follows. Process for the preparation of layer systems according to one of the claims from 1 to 6, wherein the introduction of the organic and the inorganic Precursors in the coating chamber in two feeders and mixing the organic and inorganic precursors takes place in the coating chamber. Process for the preparation of layer systems according to one of the preceding claims, in which the functional layer is part of an interference-optical Layer system is. Process for the preparation of layer systems according to one of the preceding claims, in which a first of the at least two layers is another one material composition as a second of the at least two layers and the at least one intermediate layer between the first and second layer is introduced. Process for the preparation of layer systems according to Claim 1, wherein the coating method CVD method, in particular PECVD, PICVD. Object with a layer system with at least two layers and at least one intermediate layer between the Layers producible by a process according to claims 1 to 11. An article comprising the features of claim 12, comprising an interference-optical layer system. An article according to claim 13, comprising a glass or glass ceramic reflector with an interference-optical dichroic mirror layer system.