CH635466A5 - OPTICAL SEMICONDUCTOR COMPONENT WITH A DIELECTRIC PROTECTIVE COVER. - Google Patents

Description

The invention relates to an optical 111 V semiconductor construction Aspects and Facet Damage in High Power Emission From (A1G element according to the preamble of claim 1. a) As CW Laser Diodes at Room Temperature "by H. Kressel

The term “optical semiconductor component” is intended to Ladany in RCA Rev., Vol. 36, pp. 231-239 (June 1975) is hereinafter used to refer to any device 40 about other aspects of the long-term reliability of laser diodes that have been reported to be a body made of a semiconductor material.

which, on the one hand, as a result of the application of voltage, despite the fact that these older studies and proposals exist, light emits, or, on the other hand, as a result of incident light, there is still a need for a coating for optical semiconductor light, which thus indicates the light. The second component, which is less than the semiconductor for optical semiconductor components, has light-emitting reflectivity and which prevents the erosion of the diodes, super-radiating diodes, laser diodes and detector semiconductors. The present invention is directed to the ren, optical isolators and phototransistors, such as those in solution to this problem.

the article “Light-Emitting Diodes” by A. A. Bergh and P. J. The solution according to the invention of this Pro-Dean is described in Clarenden Press, 1976. blems an optical III-V semiconductor component with the im

The development of optical semiconductor components 50 claim 1 specified features. Advantageous Wei has reached a level which makes the application in optical developments of the invention likely to result from the dependent communication systems. Claims.

Among these optical semiconductor components, in particular, it has been found within the scope of the invention that lead laser diodes are particularly well developed, which consist of a silicate glass, in particular as a coating material for protecting gallium arsenide substrate, on which optical semiconductors are epitaxially formed Components and for adjusting the applied layers of germanium or tellurium, which in turn is suitable for surface reflectivity. The coating doped with gallium arsenide and gallium aluminum arsenide can be easily formed on the semiconductor material by sputtering a light-emitting p-n junctions. To be applied prefabricated vitreous body; the combination of these layers are methods such as the liquid phase episodes of the prefabricated vitreous body, and the molecular beam epitaxy has been successfully applied in such a way that suitable thermal and optical properties have been selected. ten are guaranteed.

Laser diodes are typically in the form of tiny. The invention is described with reference to the

Chips produced, the size and shape with Salzkör- Fig. 1 to 3 explained in detail; They show: FIG. 1 are comparable in schematic form; on these chips are electrodes with a lead silicate protective coating on two, to the shear and greatly enlarged representation a laser diode with interfaces parallel to egg-epitaxial surfaces;

brings. Of the four, perpendicular to the epitaxial layers in FIG. 2, the refractive index and

Interfaces are typically two interfaces on the linear expansion coefficients of lead silicate glass as roughened and two interfaces represent gap surfaces which are a function of the glass composition; and partially reflecting mirrors are used, so that a Fabry-Perot Fig. 3 in a graphical representation of the light emission of a

3rd

635 466

GaAs laser diode leads before and after the application of a coating ner stronger linear function of the diode current. This lead silicate glass on a light-emitting boundary surface advantage is based on the reduced che. Boundary surface reflectivity in the presence of the

As can be seen from FIG. 1, the laser diode has a coating and can not only be implemented with laser diodes, GaAs substrate 1, an electrically active layer 2, a waveguide 5, but also with other light-emitting optical semiconductor strips 3, lead silicate glass coatings 4 , an electrical counter component. In the case of photodiodes, there is the de-clocking spot 5 and an electrical connecting wire 6. The advantages which can be surpassed in an increased sensitivity of the ge 4 are expediently by atomizing a pre-coated diode; In addition, the shaped glass body is applied in all cases, which has the desired coated optical semiconductor components effectively before composition. The finished coverings have a uniform composition due to the harmful influences of the surrounding atmosphere, adhere well and are free from needle protection.

holes. Coatings whose thickness is the 'A wave

The representation according to FIG. 2 is based on the contributions of the length of the light passing through the surface - “Properties of Glass”, speaks by GW Morey, p. 375 (2nd edition, the reflectivity of the coated surface appeared by Reinhold Press, 1954); and «The Constitution of is not worth mentioning. Such coatings can be used to protect the Lead Oxide Silica Glasses: II, the Corrélation of Physical Pro surface; the composition of this perties with atomic arrangement ”by GJ Bair in Journal of Coatings can be selected mainly in view of the thermal the American Ceramic Society, volume 19, pp. 347-358 (1936) and compatibility with the semiconductor material, can be helpful for selection of glass compositions in the coating with the optical thickness of 1A of the wavelength are particularly suitable as an anti-reflection coating with regard to the refractive index or the linear expansion. If such are coefficients of application. For example, it can be seen that a covering or coating consists of a glass whose Bre molar ratio of approximately 34:66 for the glass constituent index, approximately equal to the square root of the Bre-PbO and SÌO2, results in a glass whose linear expansion boiling index is the semiconductor material, these overefficiencies can closely match that of GaAs. Alternatively, trains serve to reduce the surface reflectivity to a molar ratio of approximately 49.5: 50.5 to a glass, hence a value of essentially zero. In addition, the refractive index m = 1.9 is particularly useful for one, the surface reflectivity on any anti-reflective coating on GaAs with a refractive index of any value between zero and the reflectivity ni = 3.61. of the uncoated surface can be adjusted by the

Lead silicate glass can also be inexpensively obtained on other semiconductor materials with a thickness in the range from '/ 4 to' / 2 of the wavelength materials such as GaAlAs, GaP, GaAsP, GalnAsP and GaAsSb 30 and by applying the composition of the glass. In more general terms, it can be selected that the refractive index of the glass corresponds to semiconductor materials whose coefficient of linear expansion approximates the square root of the refractive index of the semiconductor material, preferably in the range from 4 x 10 "6 / ° C to 14 x 10" 6 / ° C.

lies, a coating of thermally compatible lead silicate glass Although a molar ratio of the glass components PbO: Si02

be applied. The composition of the lead silicate glass of 49.5: 50.5 for an anti-reflective coating on GaAs is optimal and should be in a range of essentially 20 mol% PbO and glasses in the composition range from 30:70 to 80 mol% SiO 2 to essentially 70 mol% PbO and 30 mol% 60:40 mol%, provided that they are in an optical layer thickness of 'A S AO2. A proportion of at least 20, and preferably 30, of the wavelength is applied, the surface reflective mole% PbO is sought in order to ensure sufficient melting ability of a coated GaAs surface on one of the lead silicate glass at relatively low temperatures to a value of less than approximately 1 % reduce. To ensure oversize. Shares of at least 30 and preferably 40 s tensions between the coating and the GaAs sub-mol% SÌO2 are aimed at, in order to avoid glass formation, the PbO part should preferably perform in the range. The presence of copper is known to be from 30 to 40 mole%. If an increase in the surface

Sodium or potassium ions aiming for the lifetime of optical reflectivity can shorten an additional diode; the proportion of such ions in the 45 che layer of a highly reflective material, such as glass coating should therefore be as small as possible. Transparent gold can be applied to the glass layer, for example oxides such as boron oxide (B2O3), aluminum oxide (AI2O3) and by means of conventional vapor deposition processes.

Zirconium oxide (ZrOî) can be tolerated in a combined proportion of up to 10% by weight; these oxides are useful, for example, to keep the coating in a vitreous state. 50 lead silicate glass containing 54 mol% PbO and 46th e.g. where high temperatures occur. Such glasses are mol% SÌO2 was cast into a disc with a diameter of 15 cm in the article “Solder Glass Sealing” by Robert H. Dalton. This disc has been proposed in a high frequency sputtering apparatus equipped with an oil diffusion journal of the American Ceramic Society, vol. 39, pp. 109-112. ratur attached. In the course of the atomization was within the

The illustration according to FIG. 3 shows the favorable effects of atomization apparatus, an atmosphere of 80% argon and genes, which can be achieved by applying a lead silicate glass coating with 20% oxygen at a total pressure of 10-2 Torr on a GaAs laser diode. Those with A and B. The cathode was supplied with a high-frequency energy amount of marked, fully drawn curves corresponding to the light 100 W, which corresponds to an average energy density of two light-emitting boundary surfaces of 0.56 W / cm 2. On GaAs-AlGaAs laser diodes with uncoated GaAs laser diodes. The double heterostructure designated with A 'and B' were lead silicate glass layers with neat, dashed lines corresponding to the light - a layer thickness in the range from 40 to 250 nm was applied, giving off a laser diode in which a light-emitting limit - the distance between the target and the substrate surface was coated with a layer of lead silicate glass. 38 mm; a deposition rate of 2 nm was obtained. Specifically, curve A 'corresponds to the light output obtained from the min. As a result, uniform, firmly adhering, uncoated boundary surface and curve B 'of the 65 layers which were free of pinholes were obtained. The through-diode emits light from the coated boundary surface of the laser- a laser diode with a 113 nm thick glass coating. It can be seen that the presence of the coating for measurements taken is shown with FIG. 3. This greater than the intensity of the emitted laser light and too thick corresponds to an optical thickness of 0.27 wavelengths.

3 2 sheet drawings

Claims (8)

635 466 2nd PATENT CLAIMS resonator is obtained. An overview of the development 1. Optical IIl-V semiconductor component with a body of laser diode technology can post “hetero-made of at least one semiconductor material, with at least one structure injection laser” from MB Panish in the proceedings of part of the body with at least a first layer of dielek - the IEEE, Volume 64, No. 10, pp. 1512-1540 (October 1976) ent-tric material, characterized in that the 5 are taken. dielectric material consists essentially of glass; The practical application of optical semiconductor devices Glass, for its part, consists of at least 90% by weight of lead oxide PbO and dementia in communication systems depends on silicon dioxide SiOa; the mole ratio between a number of device properties; some of these PbO and SÌO2 ranges from 20:80 to 70:30. Properties again depend in a characteristic form 2. Component according to claim 1, characterized in that the interface qualities include the constancy that the molar ratio is in the range from 30:70 to 60:40, against the influence of the surrounding atmosphere and 3. Component according to claim 1 or 2, characterized gekenn- the extent of the reflectivity of the interface. Indicates that the semiconductor material has a linear expansion, for example, a low power coefficient in the range from 4 x 10_6 / ° C. to interface reflectivity is required for light-emitting diodes in order to achieve a maximum 14 x 10 ~ 6 / ° C. To achieve 15 times light emission. In the same way for photodio- 4. The component according to claim 3, characterized in that a low interfacial reflectivity detects that the semiconductor material is a material from the group GaAs, desirable to a maximum sensitivity of the diode GaAlAs, GaP, GaAsP, GalnAsP and GaAsSb. to achieve. In the case of laser diodes, it has been recognized that 5. The component according to one of claims 1 to 4, characterized in that even with relatively moderate energy values, an erosion of the mirror indicates that the semiconductor material is GaAs; and that the gel interface can shorten the life of the diode. The molar ratio is in the range from 30:70 to 40:60. eliminating these problem areas is the use of dielectric 6. Component according to claim 1, characterized, see protective coatings on the light-emitting boundary surface that the component has been proposed a laser diode with a light-emitting or facets of laser diodes, is the pn junction, the optical reflectors and electrical with the articles “Control of Facet Damage in GaAs Laser see Connections. 25 Diodes »by M. Ettenberg, H. S. Sommers, H. Kressel and 7. The component according to claim 6, characterized in that H. F. Lockwood in Applied Physics Letters, Volume 18, No. 12, p. That the optical reflectors are mirrors made by Spai-571-573 (June 1971); as well as "AI2O3 Halfwave Films for long-preserved, parallel boundary surfaces of the body (l) LifeCWLasers" by I. Ladany, M. Ettenberg, H. F. Lockwood are formed. and H. Kressel in Applied Physics Letters, Volume 30, No. 2, p. 8. The component according to claim 7, characterized in 30 87-88 (January 15, 1977) are for this purpose in particular that the plane of the p-n junction is oriented perpendicular to the plane of the coatings of silicon dioxide (SÌO2) and aluminum oxide mirror. (AI2O3) has been proposed. With the articles «Influence of Device Fabrication Para- meters on Graduai Degradation of (AlGa) As CW Laser Diodes » 35 by I. Ladany and H. Kressel in Applied Physics Letters, Volume 25, No. 12, pp. 708-710 (Dec. 15, 1974); and «Reliability