DE1923980A1 - Process for the production of layers similar to glass by vapor deposition on a substrate in a high vacuum - Google Patents

Description

DR.HANS GÜNTHER KIONKA 1 Q 9 ^ Q 8 Π Patent attorney 62 Wiesbaden »« rf * ^ ^ V U

LUztstrafi 17 Telephone 372850

New phone number 521135

JENAer GLASWERK 3 P 304, Ki / Re.

SCHOTT & GEN.

6500 Mainz
Hattenbergstrasse 10

Process for making glasätmäriefeea? Layers by vapor deposition on a substrate in a high vacuum

The invention relates to a method of manufacture glass-like layers by vapor deposition on a substrate in a high vacuum.

For many purposes it is important to have glass-like layers to be generated by vapor deposition, be it for mechanical or chemical protection, for the production of antistatic coverings, for the production of microcircuits and the like.

It is now known to produce such layers by applying the glasses in question by cathode sputtering. Such systems are very expensive, however. It is also known to produce such layers by electron bombardment of suitable glasses. These glasses have to be heated very high. The composition of the glasses must therefore remain within relatively narrow limits, since z. B. If the content of relatively easily evaporating substances is too high, they escape as bubbles with violent splashing due to their high vapor pressure. So z. B. the content of boric acid and alkalis is limited to a little · mol percent.

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The object of the present invention is a method for production glass-like layers by vapor deposition on a Substrate in a high vacuum, which is easy and cheap to carry out and allows a much greater variability of the composition.

This object is achieved in that the vaporizable material consisting essentially of a relatively easily meltable borate and / or phosphate of the alkalis and / or exdalkali.

It is useful if the easily fusible borate is a tetraborate of one or more alkalis. These go at particularly low temperatures in the thin liquid state and evaporate quite uniformly and at such low temperatures that one normal line-heated boat can use. The vapor pressure in the bell jar remains very good.

Furthermore, the easily fusible borate and / or phosphate can contain _{additions of rare earths and / or Al 3} O _3. This ensures that the substances in question are less prone to splashing. At the moment, we can only speculate about the reason for this. Perhaps they act as condensation nuclei during the degassing of the material, perhaps they bind free boric acid. ■ '

According to the broad embodiment of the invention, at the same time or almost at the same time as the easily meltable material, a high-melting material or material that is only thinly liquid at high temperatures, difficult to evaporate but without decomposition, inejbesonde xe SiO, and / or 4 ^ 2 ° 3 ^and / or rare earths, whereby these substances can be present as mechanical mixtures or as compounds. Through this

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once achieved that the composition of the glasses .sich von Borsau rearmen or alkali poor can change within wide limits Glasses to boric acid-rich or alkali-rich glasses. This affects the mechanical properties, such as thermal expansion, Brittleness, on the thermal, e.g. B. softening, and on the chemical properties.

Here, the homogeneous mixture takes place only within the formed Layer «Easily vaporizable substances may only contain such large quantities in the part that is difficult to vaporize be that their partial vapor pressure in the mixture in the same The order of magnitude is the same as that of the main constituents, which are difficult to evaporate. Glass that evaporates uniformly at high temperatures can be used as the high-melting point material will. If such a glass is used, a particularly good homogeneity of the vapor-deposited mixture is achieved, especially after additional tempering.

It has also proven to be useful that the used Substances made from pre-melted or sintered material exist.

In addition, at least one undecomposed volatile Fabric can be vaporized at the same time.

Not only can optical and electrical properties, such as refraction, dispersion and conductivity, but also the mechanical character, i.e. thermal expansion, brittleness, Affect attenuation, etc., without losing the advantages of glassiness. The additional substance can for example being a fluoride “It is well known that such euorides possess the advantage of being particularly easy to vaporize in a high vacuum. Lead fluoride has emerged from the fluorides, proved to be particularly favorable. Let electrical effects

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in particular by evaporation of lower uniformly evaporating Oxides such as SiO or TiO can be achieved. In this case, electronic conductivity occurs in some cases.

If a metal is used as an additional substance, this can be used, for example, to produce colloidal colorations for light filters can be achieved. Such colorations are known per se, but their introduction into the layers according to the invention is Often particularly advantageous because of the great hardness of such layers.

Good layers are also obtained especially when the high-melting point or, at high temperatures, thin-bodied material rial is evaporated by electron bombardment. In many cases this is the only way to achieve sufficiently high evaporation temperatures and thus to achieve sufficient evaporation rates.

Tempering after vapor deposition leads in many cases to improved tightness and homogeneity.

In a preferred embodiment, the substances can lie on top of one another as plates and under the electron beam walk past together.

In the drawing, an apparatus for carrying out the method according to the invention is shown schematically.

In a vacuum bell jar 1, which is connected to the line la to a high vacuum pumping station 2 is connected, is at .3 the substrate, z. B. a plate made of a chemically sensitive optical glass that is cleaned in the usual way and z. B. is prepared by blending. In the boat 4 made of tantalum degassed K-tetraborate is melted, the electron

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Gun 5 shoots the electron beam at 6 on the plate 7 made of a uniformly vaporizable glass, which consists essentially of SiO ₂ with low levels of alkali and B ₃ O ₃ . 8 is a swing-out flap that can be used to keep the flow of vaporization away from the substrate.

The temperature of the boat 4 and the electronically heated glass plate is adjusted beforehand so that the evaporation rate from the boat 4 is between 10 and 15% of the evaporation rate of the glass plate. Is the latter z. B. six interference orders for light of A = 546 to / min, the evaporation rate from the boat 4 is an interference order / min. The current values for heating the boat 4 are to be set in a known manner so that the evaporation rate is constant over time. After a suitable heating-up time, which is necessary to achieve constancy of the evaporation rate, the flap 8 is opened until the desired layer thickness is reached.

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Claims (13)

Claims: 6 1. Method of manufacturing glass layers through Vapor deposition on a substrate in a high vacuum, characterized in that the vaporizable material consists essentially of a relatively easily meltable borate and / or phosphate of the alkalis and / or alkaline earths which are degassed in the melt flow consists. 2. The method according to claim 1, characterized in that the Easily fusible / borate is a tetraborate of one or more alkalis. 3. Process according to claims 1 and 2, characterized in that the easily meltable borate and / or phosphate contains rare earths and / or Al ₂ O-. 4. The method according to claims 1 to 3, characterized in that at the same time or almost simultaneously from the easily fusible material still a high-melting or only thin liquid at high temperatures, difficult to evaporate, but without decomposition material, in particular SiO ₂ and / or Al ₃ O ₃ and / or rare earths evaporated wild, whereby these substances can be present as mechanical mixtures or as compounds. 5. The method according to claims 1 and 4, characterized in that the high-melting ^ material from a largely ^ consists of uniformly evaporating * glass at high temperatures. 6. The method according to claims 1 to 5, characterized in that the substances used from MDrgeschmolzenem or sintered material. 7. The method according to claims 1 to 6, characterized in that in addition at least one undecomposed volatile substance is vaporized at the same time. 009-84 8/06 8. The method according to claim 7, characterized in that this substance is a fluoride. 9. The method according to claim 7, characterized in that one of the additional substances consists of SiO or TiO. 10. The method according to claim 7, characterized in that one of the additional substances is metal. 11. The method according to claims 1 to 10, characterized in that that at least the high-melting point or, at high temperatures, low-viscosity material by means of electron bombardment is evaporated. 12. 'Method according to claims 1 to 11, characterized in that that the layers are tempered after vapor deposition will. 13. The method according to claims 1 to 12, characterized in that that the substances lie on top of one another as plates and pass together under the electron beam. 00 9848/0604 Blank page