RU2529443C2 - Glassy composition manufacturing method - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention relates to lighting engineering, namely the manufacture of light-emitting semiconductor devices with the substrate from amorphous mineral glass. The glassy composition on the basis of mineral glass containing oxides of elements of groups II, and/or III, and/or IV of periodic system, differs by that the surface of the glass is coated with the grown layer of conducting and light-emitting semiconductor compound of the type A²B⁵, and/or A²B⁶, and/or A³B⁵, and/or A⁴B⁶. The method of manufacture of glassy composition is also offered on the basis of mineral glass containing oxides of elements of the groups I, I and/or III, and/or IV of periodic system, where for formation on the glass surface of the layer of conductive and light-emitting compound of the type A²B⁵, and/or A²B⁶, and/or A³B⁵, and/or A⁴B⁶ the glass is exposed to heat treatment by heating in neutral gas at the temperature 500-5000° C, the glass is doped before or during the heat treatment by the element of the groups V and/or VI, oxygen is removed from the heat treatment zone.

EFFECT: invention provides a possibility of forming of forecasted semiconductor compounds of various compositions.

6 cl

Description

The invention relates to lighting engineering, namely the manufacture of light-emitting semiconductor devices on a substrate of amorphous mineral glass.

As a converter of electrical energy into a light emitting diode, it is characterized by external efficiency (or efficiency). The efficiency of LEDs is low. In most cases, it does not exceed 0.5 ... 5%. This is because light is difficult to bring out of the semiconductor. At a high value of the refractive indices of the semiconductors used (for gallium arsenide n = 3.3, for air - I), a significant part of the recombination radiation is reflected from the semiconductor-air interface, returns to the semiconductor and is absorbed in it, turning into heat. Therefore, the average brightness of LEDs and their output power are relatively small. In these parameters they are inferior to incandescent bulbs, in the rest they surpass them (www.about-led / materials.html).

For decades, the blue laser has been an unattainable dream in laser technology. Since red and green lasers were already invented, it remained to make blue - and by combining them you can get white light, which means you can replace incandescent lamps. It was decided in 1993 by a certain Shuji Nakamura from the then little-known small Japanese company Nichia Chemical Industries Ltd. In 1991, he grew single-crystal gallium nitride films on sapphire substrates. Then he solved the problem of obtaining monocrystalline indium gallium nitride, which is necessary for obtaining the LED structure. Finally, in 1993, he made the first commercial blue LED / LED / based on the GaN-JnGaN structure ... But bulk gallium nitride, as it was not 18 years ago, is still not there. More precisely, it seems to be, but unacceptably small in size, and at a price much more expensive than gold, if you take in weight (www. Ro nitridhoi doroge to svetu).

It is known: with a decrease in the partial pressure of oxygen in the surrounding gas environment, favorable conditions are created for spontaneous decomposition of oxides. The direction of the oxidation (reduction) reaction of the metal is determined by the temperature and pressure of oxygen in the environment.

If the oxygen generated during dissociation of the oxide is continuously removed from the treatment zone so that the residual partial pressure of oxygen remains less than the equilibrium pressure at a given temperature, then oxides will be reduced on the processed material.

Significantly reduce the partial pressure of oxygen in a gaseous medium in two ways: by creating a vacuum with a certain degree of rarefaction of air and filling the space surrounding the product with an inert gas [1].

It is known: glass has a relatively low refractive index (-1.5).

The centuries-old history of glassmaking is associated with the manufacture of silicate glasses based on the Na ₂ O · CaO · GSiO _{2 system} . Only in the second half of the twentieth century was it shown that sodium-calcium-silicate glasses constitute a small part of the boundless world of inorganic glasses.

Numerous oxide multicomponent glasses containing oxides of Ca, Mg, Ba, Zh (group III) are now known; B, Al (group III); Ge, Sn, Pb (group IV); P, As, Sb (V group of the periodic system). These and other additives in glass are used to control the softening and full melting temperature, KTLR, strength, resistance to aggressive environment, appearance, color.

A known method of imparting light-emitting properties to glass. Mineral glasses containing oxides of elements of group II and / or group III of the periodic system are heat treated in a nitrogen atmosphere at a temperature of 500-1200 ° C in a container for dissociation of oxides. By converting the oxides of these elements on the glass surface to nitrides, the resulting glassy composition becomes electrically conductive and light emitting when an electric current is passed. In the vitreous light-emitting composition, it is additionally possible to introduce elements of the V and / or VI groups of the periodic system. The container for heat treatment of the glassy composition consists of a heat-resistant shell and contains an oxygen absorber in the internal volume. The access of the surrounding atmosphere to the internal volume of the container is limited. It is possible to increase the radiation area by applying the above compositions in the form of a melted coating on heat-resistant substrates. By adding insignificant amounts of oxides forming colored silicates, any radiation color can be obtained [2].

A glassy composition is proposed, consisting of mineral glass (containing oxides of elements of the II, and / or III, and / or IV groups of the periodic system), with a conductive and light-emitting layer of a semiconductor compound of type A ² B ⁵ grown on its surface, and / or A ² B ⁶ , and / or A ³ B ⁵ , and / or A ⁴ B ⁶ .

It is proposed that the heat treatment of glass containing oxides of elements of the II, and / or III, and / or IV groups be carried out in an inert gas (for example, argon), with the indispensable removal of oxygen formed during the dissociation of oxides on the glass surface (with oxygen scavengers; removal oxygen from the treatment zone with a flowing inert gas having a low partial pressure of oxygen impurities present). The elements of group V and / or VI of the periodic system are introduced into the glass or on its surface before or during the heat treatment. (The introduction of impurities of a certain concentration on the processed substrate is well established in the technology of manufacturing semiconductor devices: preliminary deposition of the necessary elements or their salts on the surface of the substrate; evaporation of an impurity sample in the heat treatment zone of the substrate, ion implantation of impurities into the substrate; supply of impurities of the necessary elements to the heat treatment zone in the stream carrier gas ...)

According to the proposed method of heat treatment on the glass surface, it becomes possible to form a predicted semiconductor compound (electrically conductive and light emitting) of type A ² B ⁵ , A ² B ⁶ , A ³ B ⁵ , A ⁴ B ⁶ , where A ² is an element of group II, A ³ - element of group III, A ⁴ - element of group IV, B ⁵ - element of group V, B ⁶ - element of group VI of the periodic system.

The estimated amount of necessary elements introduced into the glass should roughly correspond to the stoichiometric composition of the above compounds, although, in all probability, bertollides of these compounds are formed.

For the dissociation of oxides on the glass surface and their conversion into electrically conductive and light-emitting semiconductor structures, the thermal process must take place in the presence of oxygen absorbers. They are also placed in a carrier gas stream entering the glass heat treatment zone.

To remove oxygen, nitrogen and an inert gas are passed through a pipe filled with copper chips and put on to a temperature of 650 - 850 ° С (higher temperatures should be avoided, because otherwise copper oxide becomes noticeably prone to decomposition with oxygen evolution), or, better through an absorption column with activated copper, perfectly functioning already at a temperature of 200 ° C.

Table: Preparation of activated copper for the purification of gases (especially inert gases and nitrogen) from oxygen.

1. Dissolve 2.5 kg of copper chloride in 20 l of distilled water, add 2.5 kg of infusoria (diatomaceous earth).

2. With vigorous stirring, precipitation at a temperature of 60 ° C with a solution of 700 g of NaOH in 7 l of distilled water.

3. The sediment is sedimented for 10 minutes, after which it is washed three times in distilled water (each time in 100 l).

4. Dry suction of the mass, dividing it into small pieces, complete drying in an oven at a temperature of 150-180 ° C, grinding to a grain size of 5 mm, dust screening through sieves.

5. Putting the drug in the furnace, passing pure hydrogen at a temperature of 200 -250 ° C to restore copper oxide, until the brown drug (oxide) at the beginning takes on a dark purple color (Cu).

6. The preparation is ready for use and heated to a temperature of 200-250 ° C is able to clean the transmitted gases from oxygen residues; after use, it can be regenerated again by reduction in hydrogen (the path just described).

The amount indicated in the table is sufficient for continuous purification of 400 l of gas containing approximately 1% oxygen. In the gas leaving the column with copper, at a total pressure of the gas to be purified equal to 760 nm Hg, less than 4 · 10 ^-5 % oxygen is contained. In large production, it is recommended to use two absorption columns, of which one alternately serves to absorb oxygen, while the other can be regenerated [3].

Since copper as an oxygen scavenger is effective in the temperature range of 200-850 ° C, at elevated temperatures, you can use alloy 46H: platinum (46% nickel, 54% iron), in the form of a wire.

Solubility of oxygen in copper: 0.0017% (wt.) At 550 ° C; 0.002% at 800 ° C; 0.0027% at 900 ° C / 4a /.

Solubility of oxygen in iron: 0.008% (wt.) At 700 ° C; 0.018% at 800 ° C; 0.029% at 900 ° C / 4b /.

The solubility of oxygen in solid nickel increases with decreasing temperature as follows: 0.012; 0.014; 0.019 and 0.020 weight. % oxygen, respectively, at 1200, 1000, 800 and 600 ° C / 4v /.

The use of iron (not in the alloy) as an oxygen scavenger is undesirable due to its corrosion instability (rusting).

After heat treatment, to prevent premature oxidation of oxygen scavengers and the surface of the light-emitting glassy composition, air should be allowed to enter the chamber (container, bath ...) with the hardening product when they are cooled to a temperature of ≤100 ° C (~ 50 ° C). At high temperatures, air oxygen inevitably oxidizes a semiconductor layer (electrically conductive and light emitting), which is formed (according to the proposed process technology) on the surface of the glass, converting it into a dielectric. A technological study will show to what temperature the surface of a glass product of a specific composition should be cooled in a protective (from oxygen) gas environment.

In the process of heat treatment, as in a liquid medium, the transfer of matter occurs more vigorously than in a solid, the dissociation of oxides becomes much more noticeable when the glass is softened (its transition to a liquid state). The lowest softening temperature of standard oxide glasses is ~ 500 ° C [5].

Option (method) of manufacturing the product. Glass grade C88-2 composition: 64.5% SiO ₂ ; 2% B ₂ O ₃ ; 4% A1 ₂ O ₃ ; 7% CaO; 5% BaO; 3% ZnO; 14.5% Na ₂ O, softening temperature 580 ° C, full melting temperature ~ 950 ° C [5], as proposed in patent RU 2436741, to be applied in the form of a glaze onto a heat-resistant (ceramic) substrate with a similar KTLR value (-9- 10 ^-6 K ^-1 ). Dilute the ground glass with water to a creamy state, apply this mass to the base (ceramics, porcelain ..., for example, by dipping), dry, melt in air and then conduct heat treatment according to the proposed method. An electrically conductive and light emitting semiconductor layer is formed on the surface of the glaze. The temperature and time interval controls the thickness of the semiconductor layer on the glassy surface of the product. The manufacture of an ohmic contact to a semiconductor surface is well established in the technology of semiconductor instrumentation (for example, by galvanic deposition of metallic nickel on the required surface, followed by soldering with fusible solder).

The above glass (C88-2) can be applied in the form of enamel onto a wire (base) made of 47ND5 alloy (47% nickel, 5% copper, iron rest, KTLR ~ 9 · 10 ^-6 K ^-1 ), but so that there is no electric shunting metal alloy glassy composition with its semiconductor surface layer, alloy 47ND5 must first be covered with a sublayer of dielectric soil (glass, ceramics ...) having a softening temperature higher than the temperature of the subsequent heat treatment of glass.

In the process of heat treatment when the above glass is doped with elements of group V of the periodic system (P, As, Sb), type A ² B ⁵ (Ca ₃ P ₂ , Ca ₃ As ... Ba ₃ P ₂ , Ba ₃ As ₂ ... Zn are formed on the surface of the glaze ₃ P ₂ , Zn ₃ As ₂ ...) and A ³ B ⁵ (AlP, AlAs ... GaP, Ga As ... ZnP, ZnAs).

When glass is alloyed with elements of group VI (S, Se, Te), type A ² B ⁶ compounds (CaSe, CaTe ... BaSe, BaTe ... ZnSe, ZnTe ...) are formed on the surface of the glaze

Lead glasses are obtained by partial or complete replacement of calcium oxide (in a glass of Na ₂ O · CaO · 6SiO ₂ ) with lead oxide PbO. When doping lead glass with elements of group VI, semiconductor compounds of type A ⁴ B ⁶ (PbS, PbSe, PbTe) are formed.

There are various methods of doping a semiconductor substrate with the necessary impurities. For example, during heat treatment, apply inert gas (argon) mixed with nitrogen or argon with PCl ₃ vapors (boiling point 76 ° C) into a closed chamber (furnace) with the product; AsCl ₃ (boiling point 130 ° C); SbCl ₃ (boiling point 223 ° C).

The above glass composition (C88-2) is not optimal for the manufacture of glassy semiconductor electrically conductive and light-emitting compositions. The glass composition can be preliminarily introduced elements of the V and / or VI groups of the periodic system in the form of their oxides.

It is known that arsenic trioxide makes glass “deaf”, i.e. opaque. However, small additives of this substance, on the contrary, brighten the glass. Arsenic is still included in the formulation of some glasses, for example, Vienna glass for thermometers (0.2%) and semi-crystal glass (0.5%). In the manufacture of enamel, 4-7% of antimony oxide is added to the glass. A large group of oxides: SeO ₂ , TeO ₂ , Bi ₂ O ₃ , Al ₂ O ₃ , Ga ₂ O ₃ - forms glasses when fused with other oxides or mixtures of oxides.

A glassy composition with a semiconductor layer on the surface can be obtained directly by pulling liquid glass from a bath with a melt (one of the methods for manufacturing sheet glass). Or according to the Czochralski method: the seed is lowered into liquid glass to wet it, and then the seed is pulled upward, rotating it. In this case, you can get both an ingot and a tube (seed in the form of a tube). The speed of rise and rotation is controlled by the size of the product.

Zonal formation of a semiconductor layer on the glass surface is possible, similar to the zone melting of silicon: the heater moves along the glass sample, converting the glass to a liquid state in the required place (with the corresponding dissociation of oxides, etc.)

Plasma welding in an atmosphere of argon or neon (with the corresponding gas impurities) provides small dimensions of the molten glass zone. In an atmosphere of argon (neon), the plasma jet is heated to a temperature of 15000-25000 ° C [6].

It is permissible to cool and heat a glass plate or a ceramic (metal) substrate with glass deposited on it. The plasma torch (plasma torch) and the substrate with glass can be moved, raised and lowered. The length of the gas stream is regulated by the pressure and volume of the gas entering the plasmatron (using a rotameter). The surface layer of glass with a plasma jet can be heated to a temperature of 25,000 ° C. Glass evaporates at temperatures above 5000 ° C.

Intensive chemical processes are much more energetic in a liquid medium (compared to a solid). Many varieties of mineral glass begin to soften at a temperature of 500 ° C. The possible interval of heat treatment of glass for the manufacture of a glassy composition is in the range of 500-5000 ° C.

Float is known - the manufacturing process of large-area flat glass. The essence of this method: an adjustable amount of molten glass in the form of a jet is poured from a glass melting furnace into a bath with molten tin, spreading over liquid tin (the specific gravity of the glass is less than the specific gravity of tin), turns into a glass ribbon with fire-polished surfaces. The process is conducted in a nitrogen-hydrogen atmosphere (hydrogen cleans the surface of liquid tin from oxide films).

This is how uviol glasses are made (increased transparency in the ultraviolet region of light with a wavelength of 280 ÷ 320 nm). These glasses transmit ultraviolet rays in contrast to ordinary glass.

The standard composition of the uviole glass: 69.5% SiO ₂ ; 5.5% CaO; 3.5% MgO; 5% BaO; 12.5% Na ₂ O; 4% K ₂ O; softening temperature 550 ° С, complete melting ~ 950 ° С.

A method for manufacturing glass with a large light emission area is proposed: in the float process, replace the nitrogen-hydrogen gas mixture with an inert gas (with a low partial pressure of the present oxygen impurity) with the addition of Group V elements (type A ² B ⁵ semiconductor compounds are formed on the glass surface) or VI groups of the periodic system (the formation of a system of type A ² B ⁶ ). (Possible joint doping with the formation of joint compounds A ² B ⁵ and A ² B ^6. )

It is easiest to feed argon gas mixed with nitrogen into a closed bath of molten tin and glass. The pressure of the incoming inert gas must exceed atmospheric pressure.

In all of the above options for the manufacture of glassy compositions, the process of heat treatment of glass should take place in the close presence of powerful oxygen scavengers. Air access to the product after heat treatment is allowed when the product is cooled (in an inert gas) to a temperature of ≤100 ° C. Further design and technological studies will show that it is possible to form a thin oxide dielectric film on the surface of the semiconductor layer of the glassy composition, with appropriate adjustment of the opening temperature of the working chamber (after completion of the heat treatment) with access to ambient air.

Information sources

1. Lashko S.V., Lashko N.F. "Soldering metals." - M.: Mechanical Engineering, 1988, p. 177-179.

2. Patent RU 2436741 “A method of manufacturing a glassy composition and a container for heat treatment” Author: Ksenofontov Oleg Petrovich.

3. Espe V. "Technology of electrovacuum materials", t.3, "Auxiliary materials", M.-D., Energy, 1969, S. 312, 320.

4. Hansen M., Anderko K. "Structures of double alloys", M., Metallurgizdat, 1962, v.2, 4a - p.647, 46 - p.730, 4c - p.1085.

5. Lyubimov M.L. "Joints of metal with glass", M., Energy, 1968, pp. 41-44.

6. Frolov V.V., Vinokurov V.A., Volchenko V.N. and others. "Theoretical foundations of welding", M., Higher school, 1970, S. 142 ÷ 149.

Claims (6)

1. A glassy composition based on mineral glass containing oxides of elements of the II, and / or III, and / or IV groups of the periodic system, characterized in that the surface of the glass is covered with a grown layer of electrically conductive and light-emitting semiconductor compounds of type A ² B ⁵ , and / or A ² B ⁶ , and / or A ³ B ⁵ , and / or A ⁴ B ⁶ . 2. A method of manufacturing a glassy composition based on mineral glass containing oxides of elements of the II, and / or III, and / or IV groups of the periodic system, characterized in that for the formation on the glass surface of a layer of an electrically conductive and light-emitting compound of type A ² B ⁵ , and / or A ² B ⁶ and / or A ³ B ⁵ and / or A ⁴ B ^{6 the} glass is subjected to heat treatment by heating in an inert gas at a temperature of 500-5000 ° C, the glass is alloyed before or during the heat treatment with elements V and / or Group VI, remove oxygen from the heat treatment zone. 3. A method of manufacturing a glassy composition according to claim 2, characterized in that the semiconductor compound is grown by moving the heater above the glass surface. 4. A method of manufacturing a glassy composition according to claim 2, characterized in that the semiconductor compound is grown on a glass coating of a heat-resistant substrate. 5. A method of manufacturing a glassy composition according to claim 2, characterized in that the composition is pulled from a molten glass melt. 6. A method of manufacturing a glassy composition according to claim 2, characterized in that the sheet glass with a large radiation surface is produced by the float method in an inert gas atmosphere.