DE19963550B4 - Bipolar illumination source from a self-bundling semiconductor body contacted on one side - Google Patents

Abstract

Bipolar illumination source made of a self-bundling semiconductor body contacted on one side, the substrate of which is transparent to the luminescence waves and connected to a structure of layers of ternary and binary III-V connections and which is set up for pseudo-lateral operation, with a mechanical bridge made of an optical plate (20, 30, 35, 102) made of a semiconductor body that is uniformly transparent for luminescence, with which at least two luminescent pillars and exactly one assigned non-luminescent pillar (31-33, 36-39, 73-74, 98; 34, 40, 43, 72, 91) are held next to one another at a desired distance,
the luminescent pillars (31-33, 36-39, 73-74, 98) having a layer structure and a luminescence-active layer (45, 75, 95, 106) and having a smaller cross section than the non-luminescent pillar (34, 40, 43, 72, 91) are formed,
all pillars (31-33, 36-39, 73-74, 98; 34, 40, 43, 72, 91) on the underside end in the same plane in a flat mounting surface,
the pillars (31-33, 36-39, 73-74, 98; 34, 40, ...

Description

The invention relates to a bipolar Illumination source from a self-bundling contact made on one side Semiconductor body, its for the luminescent waves transparent substrate with a structure from layers of binary or ternary III-V compounds connected and for pseudo-lateral operation is set up.

• (a) Fernbedienungsanwendngen und Lichtschranken, sowie
• (b) der stationären oder mobilen, impulsartigen oder kontinuierlichen Beleuchtung eines zu überwachenden Geländes, Raumes oder Fahrzeugs zum Zweck der Zugangs-, Anwesenheits- oder Bewegungskontrolle oder
• (c) der Kurzstrecken-Datenübertragung und
• (d) der Informationsdarstellung auf einer Anzeige

eingesetzt werden.The lighting source should be used in service, protection, security and alarm systems such as

• (a) remote control applications and light barriers, as well
• (b) the stationary or mobile, pulse-like or continuous lighting of a site, room or vehicle to be monitored for the purpose of access, presence or movement control or
• (c) short-range data transmission and
• (d) the presentation of information on a display

be used.

The need for protection and security come other barrier and property protection systems, such as walls, grids, etc. Access blocks only with massive effort.

With the help of surveillance systems and new ones Lighting sources can better meet this need. A special accent here are lighting sources from the People cannot be noticed. Until then, preferred the use of motion detectors maintained as passive detectors heat sources like birds, and responded to pets as much as to human intruders. By a camouflage of the heat sources with the help of appropriate masking, however, these detectors were to outsmart. Light barriers with one or more pairs of luminescent diodes and photo transistor are harder to deceive, but they also speak with harmless interruptions.

Also sound and ultrasound signals have been monitored Transfer rooms and on the changes of the reflected signals checked. from Wind-moving flora or harmless animals could invaders to pretend.

Radar and microwave based surveillance of air spaces and waters have been in use for decades, but for most users far too expensive.

With the help of a stationary or rotating infrared laser diode could rays reflected from moving objects on suitable ones Recipients already something cheaper determine. Independently from the effort involved in image evaluation with IR photo receivers the relatively expensive IR laser extended the application to other areas of application.

Illumination sources, their performance at lasers approached, but at which manufacturing and operating costs are significant lag behind, are also known. The invention aims for such lighting sources both on an improvement in the yield of reliable ecological Manufacturing, as well as a cheaper Conversion of electrical to optical energy independent of the operating time.

As a construction option for luminescent diodes is the formation and arrangement of the contacts on the same surface side, the unobstructed light emission from a free surface and the transition from vertical to Lateral operation known.

To suppress losses due to radiationless recombination on the surface of GaAsP-GaP or GaP-Planar diffusion diodes contacted on one side, in DE 27 12 412 A1 proposed to displace the currents of the minority charge carriers into deeper lying areas by means of a field plate effect. The majority carriers should be introduced into the n-type luminescent epitaxial layer via a highly doped n-type connection region in a higher n-type layer. This layer structure and the realization of similar diffusion zones do not work in the same way with AlGaAs-DH structures.

In GB 2,019,643 A proposed a luminescent diode with a layer sequence of Ga _1-x Al _x As on a GaAs substrate, in which an increased external quantum efficiency and a reduced internal absorption can be realized. For this purpose, an active n-luminescent layer made of Ga _0.90 Al _0.10 As: Te (5.10 ¹⁷ cm ^-3 ) with a degree of compensation ND / NA of 10 and the thickness of an absorption length, for example 3 μm, of two cladding layers made of p-Ga _0.70 Al _0.30 As: Zn (5.10 ¹⁷ cm ^-3 ) and n-Ga _0.70 Al _0.30 As (5.10 ¹⁶ cm ^-3 ) coated. A p + -conducting ring zone, doped with Zn (10 ¹⁹ cm ^-3 ) surrounds the active luminescent layer on the outside and creates a connection to the lower lying p + -conducting cladding layer. The p + -conducting ring is provided with a p-contact made of Au-Be or Au-Zn and the n-conductive cladding layer with an n-contact coplanar on the same surface. The peculiarities of the active luminescent layer (thickness relative to the absorption length, degree of compensation and doping) ensure photon recycling of the photons that have returned to the luminescent zone through multiple reflection. The photons are converted back into radiation-recombinable charge carrier pairs and can then leave the semiconductor as new photons with a more favorable angle to the exit surface.

In EP 0 720 241 A2 an LED structure for fiber optic communication technology has been specified with which the emission in the near field a precisely aligned light emitter made of InGaAsP on an InP substrate can be coupled into a fiber in a precisely directed manner. The structure aims to overcome difficulties in mass production, especially adjustment, and to avoid wire bonding techniques. To achieve this goal, as in 2 shown an LED chip 1 from an n-type layer 2 and a p-type layer 3 educated. A pit 4 severed upward from the surface 5 the bottom of the p-type layer 3 starting from this p-type layer 3 , The pit 4 extends to the n-type layer 2 and has on both sides of the floor 4c a first side wall 4a and a second side wall 4b , It serves as a spacer between a thick p-type bond pad 13 to p contact 7 and a thick n-type metallic bond pad 14 to the n contact 6 , The bond islands are on thin metal surfaces 12a and 12b , The n contact 6 consists of Au / Sb / Au and extends from the surface 5 over the first side wall 4a the pit 4 to the ground 4c the pit 4 and contacted on the ground 4c the pit 4 the n-type layer 2 , A mask 8th made of dielectric material such as Si ₃ N ₄ , SiO ₂ or photoresist with a thickness of 200 nm limits the n-contact 6 , Towards the projection of the p-contact 7 A lens is located behind the pn junction to improve the coupling of the emission into a fiber 9 , The Lens 9 is inserted into a cavity similar to the Burrus structure. The contact is now made with solder bumps, with a dielectric film spreading the solder over the metallic bonding pads 13 and 14 prevents beyond. The size ratios of 2: 100 between the contact area of the p-contact 7 and the pn junction area 11 indicate that only a small part of the DH structure in the p-type zone for direct operation of the fiber behind the lens 9 needed and no value is placed on expanding the current.

The geometric shape of the semiconductor body in the scattered tiles and the individualization of the luminescence active zone before the decomposition of the Discs hangs right from opting for one of the two main variants, the edge or surface emitters, from. While the edge radiation predominantly is used for laser diodes, luminescent diodes are preferred on surface spotlights back. Laser diodes owe their efficiency to the application of gap areas the exit surface the emission. In the case of luminescent diodes, the chip body is passed through a separation process with the help of scoring and breaking technology, by one sawing with the help of diamond discs or wires or a separation etching process molded after selective masking of one or both major surfaces.

The cuboid or columnar shape the chips are very common thanks to their simple manufacture.

It is part of a long-maintained Assembly practice, such or similar Luminescent diode chips in housing reflectors insert or arrange next to it.

The multitude of the other geometry variants the luminescent diode chips could economize on the use of materials do not take into account in the same way.

The developed for fiber optic communication technology Burrus structure is through a DH-AlGaAs semiconductor chip with a two-sided Contacting and a hollowed out GaAs substrate part marked directly under the optically active zone. The surface with the luminescence active layer carries a 50μm current contact.

After DE 25 42 072 A1 the large-area direct contact of one side of the burrus structure was abandoned in favor of the formation of a mesa with bevelled edge surfaces. The radiation that propagates parallel to the transition essentially becomes after the reflection. deflected perpendicular to the pn junction plane. In order to achieve the 45 ° inclination of the edge of the edge surface required for maximum radiation, a diffusion-limited etchant, which is favorable for the Ga _x Al _1-x As-GaAs system, was used.

In place of the mesa shape, a V-shaped pit can also be used to collect light, which according to the JP-A 62-25472A is placed in a ring around a pn transition surface and also forms an angle of 45 ° with the light emission area. This makes it easier to direct the light past the rear contact. The diversity of the coupling-out variants of the light beams at relatively small pit depths is indicated here, but is far from being fully illustrated or even used.

Spherically polished chip body with an active zone in the focal point of a semiconducting lens body after the DE 28 25 387 C2 or US 4,017,881 ensure good decoupling over the lens surface. They operate at different solid angles depending on the distance between the lens cap and the emission plane. Only if the light emission over the active area of the np junction can be kept really uniform can it be used in optical communication technology or high-precision distance measurement without difficulty. In order to even out the current density and with it the light emission, a single layer with low specific resistance and adapted thickness or a double layer of equal strength with a thin, highly conductive and a thick, high-resistance layer is connected between the substrate and the np junction.

If this semiconductor element is to receive both electrodes on the surface opposite the lens, the n ⁺ p transition must first be limited to a partial surface by an annular incision. Restriction is however that outside the incision to remove the blocking effect of the n ⁺ p junction, the n ⁺ layer is completely redoped there and brought into the same type of guidance as in the additionally switched on layer under the lens. This creates a p ⁺ p transition, which enables a low contact resistance to the contact metal.

The incision does not necessarily have to be right into the highly conductive crystal layer, but only close to reach them.

higher beam strengths or greater brightness in Sources for Lighting purposes can only be achieved by means of the better Conductivity, new distances between the lens and the emission plane or other incision dimensions cause.

Nevertheless require such centrally symmetrical Structural structures in their elaboration but a high individual Effort per chip.

A uniform GaP semiconductor body was obtained after JP 52-124885 A a flat, transparent electrode on a first surface and an epitaxial pn junction on a second surface. Two MESA structures are formed on the latter surface by etching. The transparent electrode is in galvanic contact with the wiring on a carrier plate.

The remaining thickness of the transparent electrode between the two MESA structures is much smaller than the height of the MESA. This creates a mechanically very sensitive stilt structure low assembly strength but certain optical advantages. by virtue of of the jump in the refractive index at the transition to air occurs GaP on all surfaces of the MESA body total internal reflection at a relatively small angle. This effect is used here for the internal control of the light radiation. The long MESA leads the light according to his Height almost as in an optical fiber to the light exit point on the transparent Electrode. Not the total amount of light distributed isotropically around the emission plane can leave the MESA as parallel light, but the local luminance is noticeably increased. irregularities this does not, however, result in the transparent electrode eliminated.

After JP 06-318731 A is the emission efficiency of the light emitter arrangement by inserting a pit between two strip-shaped MESA, similar to that EP 0 720 241 A2 , reached, with the emitting mesa stripe having an oblique slope already mentioned on both sides of the stripe.

According to Franklin-AR et al., Conical chip bodies with an emission zone lying transversely to the cone and deflecting lateral surfaces. and the publication in Journal of Applied Physics 35 (1964), pp. 1153-1155 in GaAs for utilizing primary reflection. To DE 198 07 758 A1 To take advantage of secondary reflections, the side surface in light-emitting elements can be designed similar to an inverted truncated pyramid and provided with a uniform obtuse angle (β + 90 °) with β between 20 and 50 °. This is a chip structure accompanied by large area losses. In order to reduce these material losses, the embankment lengths would have to be shortened considerably without reducing the detection of the primary and secondary rays.

To reduce costs, instead of on-chip lenses often lenses external to the chip and other imaging elements are also used. However, there are already losses when exiting the chip and when imaging in outer optical Components. Sublime, over the general chip area Reaching and mesa-like luminescent zones became a relief very early the adjusted mounting of imaging beads for improvement coupling into fibers.

The mesa structure can be used to control the luminescence within the chip US 4,742,378 , where a column is placed vertically on a chip plate into which a pn junction contacted in the form of a jacket continues. The luminescence is directed in the direction of the optical axis of the column and emitted from a tubular pn junction. The metallic jacket electrode does not shade the end face of the column, so that the luminescence can easily be taken over in optical fibers. However, this mesa structure of the laser or luminescent diodes is not accessible to one-sided contacting and simple manufacturing technology.

With the transition to one-sided contacting powerful lighting sources arise compared to bilateral source the requirements of sufficient electrical Supply of the active luminescent layer with charge carriers of both Types of a surface the substrate-oriented steering and unilateral decoupling of the Photon emission and control and dissipation of thermal losses the electro-optical conversion.

An additional, under the luminescence active Zone buried distribution layer has to supply a first type of charge to care.

From the same, already once contacted surface off, the supply with the second charge carrier type is even and without selective overload make.

The luminescence emitted isotropically is independent of this to bundle directionally from the active zone. The problem is that the distribution layer appears light-diverting and the directional extraction of optical energy reduces.

The danger of happening simultaneously Deriving the photons from the active zone into one not for bundling and decoupling suitable direction is to be eliminated.

It is no longer permissible that the desired surface emitter is in its emissive area is defined solely by the chip edge length. A restriction to part of the chip area must be made. The isotropic emission distribution must nevertheless be completely redirected to a single surface within the chip and bundled into a given solid angle.

The invention has for its object a to create bipolar structure in which the individualization the luminescence active zone and its subsequent electronic supply in every semiconductor die is designed so that one is possible high optical output power per plate can be achieved but nevertheless the semiconductor material is used economically and none complex molding cycles are required.

The structure is supposed to be the supply with load carriers both types temporally and locally evenly and up to the highest Ensure current levels, ensure good use of space and breakage stability and if possible simple joining technology the contact electrodes effectively dissipate the thermal losses allow the electro-optical conversion.

This task is due to the characteristics of claim 1 solved. Appropriate configurations are the subject of the subclaims.

That is the basis of the patent claims lying structure principle is based on the subordination of the optical Requirements under the route design of the feed and Distribution of the electrical charge carriers of both types of charge and of rapprochement a barrier-free mechanism change of thermal conductivity during the transition from the phonon-based for electron-assisted Process on contact via the pn junction.

The main idea here is downsizing the lateral dimension of the emission zone through the segmentation the luminescence active area, the reduction in the thickness of the optically used layer package and lowering the heat build-up Character of the layers between the pn junction and the metal contact by grading the layer composition in the pre-contact zone.

A platelet structure is created at of the relevant product functions such as feeding and Distribution of electrical energy, its conversion and decoupling as optical energy and the derivation of thermal losses with a high effect in and on the plate expire and hardly any support from additional, external elements require.

In realizing the guiding principle from the spatial Limitation of the lateral extent of the optical-electronic layer package assumed the shape of pillars in the optical section. A cone-shaped Extension of the cross-sectional dimensions the pillar in the direction of an optical connecting the pillars A plate of sufficient breaking strength is used as intended.

The most important feature of the invention is the division of the luminescent pillar type into two or several pillars with smaller cross-sectional dimensions. Are with this characteristic not only advantages in manufacturing costs, but also in the optoelectronic properties of the end product.

The pillars can be used as truncated pyramids with equilateral or rectangular bases, as a truncated cone with round, elliptical or crescent-shaped base areas or as a trapezoidal Executed rings his.

The height of the pillar must be the largest in straight, lateral connection, which can be drawn on the pillar (in the following referred to as the diagonal of the pillar). Larger diagonals require larger pillar heights. The visually usable pillar height can be increased by a raised step in the surface profile of the substrate.

Through a previously created lead the optical disc, over then the entire layer package including the distribution layer for negative charge carriers is drawn the derivation and the directed one succeeds Redirection of the part that spreads laterally in the layer plane the isotropic luminescence distribution.

The arrangement of an imaging lens made of semiconductor material with increased Focal length, or of optical fibers with adapted fiber diameter the optical plate in the optical section of the chip increase the bunching effect in the far range.

The LED chips are for easy contacting with their mounting level on a printed circuit board attached from silicon. This circuit board can be useful as Assembly tub be formed.

For the automatic Control of the luminescence intensity of the lighting source It turned out to be very advantageous if one of the rectifiers usable DH layer structures operated as a photodiode in the reverse direction and the measured photocurrent becomes the evaluation standard for the retention or correction is made in the control loop of the injection current.

Finally, a special frame-shaped pillar shape, the others Pillar of a chip connected encloses to build an automatic hermeticization of the optoelectronic active Areas of the chip are used. Then even an additional one The chip-chip carrier system is not capped. Doing so will adjust the dimensions of the luminescent Pillar to the dimensions of silver cushions in depressions of the Chip carrier plate respected, can the thermal resistance of the entire lighting source very advantageously.

Other advantages and details The invention will become apparent from the following, based on the drawings declared embodiments out. The drawings show:

1 a lighting source with two functional sections and splitting the optical section into several sub-diodes
(A) simple luminescent diode (after 2 )
(B) several pn junctions connected in parallel against a common cathode,
(C) Chip layout with in-line arrangement of the pn junctions
(D) Arrangement of the chip elements in the disc assembly,

2 an embodiment of the Burrus structure according to Dautartes (prior art),

3 other variants for the chip layout in the review
(A) square chip contour with corner placement of three pn junctions
(B) central symmetrical placement of four pn junctions of the optical section within a closed, circular pillar,
(C) a section along the line A-A '

4 a lighting source with
(A) incomplete and
(B) with complete decoupling of the luminescence from the optical section in the desired direction,

5 a source of illumination
(A) with improved integration of the distribution layer in the optical section and
(B) an optimized coupling area,

6 a mounting structure of the lighting source,

7 2 shows a sectional view of a lighting source with deflection and bundling within the chip,

8th two extended, attachable transparent windows with different optical elements
(A) with lens elements
(B) with fiber elements,

9 Characteristics of the new lighting source
(A) Flow current characteristics and
(B) Radiation power from chips with one pn junction and with several pn junctions,

10 an equivalent circuit diagram of a self-controlled lighting source and

11 a structure of a lighting source with automatic hermeticization of the optoelectronically active zone
(A) in top view
(B) as a cross section.

1st embodiment

The demand for increased optical power from a semiconducting lighting source can best be met with the structure concept of segmented isotropically emitting emission zones. This shape can be created if the definition of the size of the luminescence-active zone in the optical section is simultaneously linked with the integration of deflection units for the luminescence from this zone. The multiple stages of the etching process for forming the cone-like pillar cross section, in particular for large pillar heights L, is undesirably complex. In detail, the pillar height L follows the greatest distance D between two points within the light emission surface or the largest diagonal of the pillar according to equation (1) at a fixed critical reflection angle θ _{crit (n} ). L = F (θ crit (n) , D) = D tan θ crit / (1 + 2tan θ crit ) (1)

The pillar height L can only be reduced if the distance D of the luminescence-active layer is reduced. According to simple luminescent diodes 1 (a) the emitted optical power with uniform luminance depends on the size of the emission area. Smears on the surface are therefore hardly permissible. However, an equally strong emission source can 1 (b) are formed from several partial diodes with smaller partial areas, but the same total area. 1 (c) shows an associated chip layout. With him are on an optical disc 20 three luminescence-active pn junctions 21 . 22 and 23 and associated anode contacts 24 . 25 and 26 in addition to a cathodically polarized contact responsible for all 28 on an n-type distribution layer 27 arranged. The anode contacts 24 . 25 and 26 lie next to each other on the same level and are located on truncated pyramid-shaped bodies or pillars. By dividing the area into three, the required pillar height L is reduced to less than 60% of its original height.

In the production of such a bipolar illumination source, a (100) -oriented, n-conducting, mechanical Al _x Ga _1-x As bridge is used as the optical plate 20 with an x-value of 0.27 ± 0.12 and a doping of <3.10 ¹⁷ cm ^-3 an n-type distribution layer 27 deposited with a significantly higher doping of (1 ± 0.3) .10 ¹⁸ cm ^-3 , a layer composition of Al _x Ga _1-x As with an x value of 0.2 ± 0.08 and a layer thickness of 30 μm , This is followed by the Al _x Ga _{1- x} As-DH layer structure with a luminescence-active GaAs layer, which is enveloped by an n- and a p-conducting ternary layer with an x value above 0.11. The DH layer structure has a total thickness of 30 μm.

The definition of the lateral size of the luminescence-active layer parts and the pn junctions 21 . 22 and 23 and their connection in deflection elements in the associated truncated pyramids towards pillars under the optical plate 20 is done by targeted etching. In order to obtain three conical pillars, use is made of the increase in the etching speed with decreasing Al content in Al _x Ga _1-x As. As a result, an x-value gradient is built up in the DH layer structure in each layer. Near the later assembly level and under the later metallic anode contacts 24 . 25 and 26 Where the greatest lateral etching removal is desired, a small x value must be observed. Towards the optical disc 20 the x-value increases linearly with the distance from the assembly level. However, the scope for using this effect for crystallographic etching is essentially limited to the x value range between 0.01 and 0.12. For this reason, additional support for the oblique etching is additionally introduced when using larger x values for the layers. The optical disc 20 is coated on the surface side of the DH layer sequence with photo-positive lacquer and formed into a first etching mask. The first mask enables etching removal of only a narrow strip around the anode contacts 24 . 25 and 26 , The resulting pyramid is smoothed and etched into the desired pillar shape to form an optical plate 20 brought expanded cross-section. The thickness of the remaining distribution layer 27 is at least 13μm. Each pillar with the luminescent pn junctions 21 . 22 and 23 and also the non-luminescent pillar with the contact 28 has a height L of 35 μm above the flat mounting surface at the end of the etching process. Only now is the metal assignment for the anode contacts applied 24 - 26 and contact 28 as well as the connection to the distribution layer 27 by vapor deposition of an Au-Ge alloy. The complete, finished pane can be separated into individual plates for the illumination sources by suitable sawing with wires or diamond plates or by scratching and breaking from the free surface side of the optical plate 20 respectively. If necessary, the two surface areas must be protected with cover foils.

1 (d) shows a disc layout with the arrangement of the chip elements in the disc association and the mirrored disposition of the elements of the adjacent lines. This disposition is advantageous for the final separation of the chips, since the parting line between the cathodically polarized contacts 28 two adjacent chips are not subject to any requirements for cone-like expansion and can therefore be carried out in a space-saving manner. To facilitate the separation, the chip lines are parallel and orthogonal to a crystallographically oriented chamfer 29 arranged.

The chip layout shows a deviation from the in-line arrangement of the anodically poled pillars 3 (a) shown. This also enables the return to square chip contours. Each of the three anodically poled pillars 31 . 32 and 33 occupies a corner on the optical disc 30 , A cathodic pole 34 takes the place in the last corner. In addition to the square ones, round or sickle-shaped pillar contours can also be produced.

Will the emission area in the chip layout after 3 (b) in four equal sub-areas 36 . 37 . 38 and 39 is divided for these pillars on an optical disc 35 because of the smaller distance D only half of the otherwise required pillar height L is necessary. The layout also shows a closed, ring-shaped cathodically polishable surrounding pillar 40 , which can be used advantageously in final assembly as explained below.

3 (c) shows a section along the line A-A ', the conical type of the pillar is not shown.

In the 4 the mode of operation of the illumination source designed according to the invention is shown, taking into account the coupling out of the luminescence from the optical section in the direction of the transparent optical plate. The perspective view of an imperfect chip structure 51 in 4 (a) shows a cathodically polarized pillar 52 and two anodically poled pillars 53 . 54 , A luminescent layer 55 is very close to the lower edge of the optical plate of the chip structure 51 , The pillar height L is too low here. As a result, an assumed starting point runs 57 outgoing beam 59 fully against the cone-like wall of the pillar 54 and is redirected from there to the optical disc. The same applies to the limit case of a beam 58 , In a half cone 60 the redirected luminescence is represented. The undeflected luminescence is, for example, due to a semi-cone 61 represented in which rays 62 a - d or by light guide effect in the distribution layer 56 transmitted rays 63 are located. The radiation in the semi-cone 61 is lost for use as a lighting source and reduces the external optical efficiency.

In contrast, one as in is more advantageous 4 (b) shown chip structure 71 , in which the cone-like pillar structure extends deeper into the optical plate and the pillar structure and pillar height L are more appropriate to the situation. This ensures that a luminescence-active layer 75 in anodically poled pillars 73 and 74 occupies a middle level and parts of a distribution layer 76 to a wall element of the anodically poled pillars 73 . 74 became. One from a starting point 77 outgoing radiation cone 80 with the marginal rays 78 and 79 is now full of the cone wall of the pillars 73 . 74 detected and directed in the desired direction.

2nd embodiment

A second way of designing the pillar structure is from 5 (a) seen. At the op table plate 20 Al _x Ga _1-x As becomes a columnar arrangement of trapezoidal projections on one surface side 41 appropriate. They are formed by wet chemical etching after photolithographic masking and jump 30 μm from the surface. The area dimensions of the projections 41 for the luminescent and non-luminescent pillars and the distances from one another are tailored to the needs of the chip layout, for example 1 (c) customized. About this redesigned optical disc 20 is now a 25 μm thick distribution layer 42 and then pulled the Al _x Ga _1-x As layer package of the DH structure with the pn junction. The layer region over the ledges 41 is covered with an etching mask. The layer parts of the DH structure are then around the luminescent pillars and up to the non-luminescent pillars 43 approach by etching to the distributor layer 42 removed again. A vapor-deposited contact layer forms a cathode contact 44 who have favourited Metal Coverage for a Route 44a and creates the connection of the contact on the cathodically polarized pillar 43 to a collar 44b at the distribution layer 42 near a luminescent active layer 45 , The optical section of this structure is now due to the inclusion of the undiminished distribution layer 42 significantly improved in the pillar structure with regard to the power supply and the effective deflection of the luminescence. The pillar height L between the lower edge of the distribution layer 42 and the flat mounting surface of each pillar is 50μm. The anode contacts 46 at the foot of the luminescent layer 45 and the cathode contact 44 at the foot of the non-luminescent pillar 43 flow on one level.

3rd embodiment:

The optimization of the semiconductor outer surfaces of the illumination source is described in the third exemplary embodiment, see 5 (b) , In the optical section S _o is the optical disk 20 on the trapezoidal projections 41 with at least two anodically poled pillars 98 occupied. A uniformly thick, n-type distribution layer 92 is from a cathode contact 93 a pillar 91 via a main line 94 supplied with load carriers. A luminescent layer 95 emits in operation at 810 nm. One over the luminescence active layer 95 in the pillar 98 lying cladding layer 96 by a p-type Bragg reflector 97 from an anode contact 99 Cut. To alloy the Bragg reflector 97 through the Au-Ge contact metal of the anode contact 99 to avoid the Bragg reflector 97 coated with a highly doped GaAs layer before vapor deposition of the metal alloy. Such reflectors are according to van der Ziel-JP and Ilegems-M, as published in 1975 in the magazine Applied Optics Vol. 14, Issue 11, pp. 2627-2630, from a stack of pairs of layers made of GaAs-Al _x Ga _1-x As formed, the x value jumping between two fixed values 0 and 0.38. The number of layer pairs and layer thickness of the individual layers is adapted to the wavelength of the reflection band and the desired degree of reflection. In the photon energy range of 1.53 ± 0.019 eV, the refractive index difference Δn is 0.25 between the two layer partners. The thickness of the binary layer d1 is 55 nm and that of the ternary layer d2 is 60 nm. With a layer stack of 25 layer pairs, a degree of reflection of over 85% is achieved with the selected luminescence band.

These Bragg reflectors 97 can be produced by molecular beam epitaxy (MBE), by atomic layer epitaxy (ALE), by epitaxy with phase-changing alternation of the deposition and interruption (phase-locked epitaxy) but also by chemical vapor deposition with the help of organometallic compounds (MOCVD).

To facilitate the decoupling of the shape of the pillars 91 . 98 and the Bragg reflectors 97 deflected luminescence becomes the exit side of the optical plate 20 with an anti-reflective layer 100 overdrawn. The anti-reflective layer 100 consists of aluminum oxide. Optionally, silicon oxide can also be used.

In 6 a housing structure for the final assembly of the lighting source is shown. Here, for example, the in 5 (b) illustrated chip with the optical disc 20 upwards and the cathode and anode contacts 93 and 99 down into a prefabricated silicon housing 133 inserted. In an assembly tub 134 of the silicon housing 133 provides a solder joint 131 a lead to the cathode contact 93 and a solder joint 132 a connection to the anode contacts 99 ago. The solder connections 131 and 132 on the other hand, wet conductor tracks 136 and 137 , Via individual vias 138 get the ladder tracks 136 and 137 a link with external connections 139 and 140 at the bottom of the silicon case 133 , The optical disc 20 is on the flat surface with the anti-reflective layer 100 with a sealing plate that is permeable to luminescent light 141 positively covered. The sealing plate 141 is with an inner wall 135 the assembly tub 134 hermetically connected. Is located in the sealing plate above the anodically poled pillars 141 an imaging curvature 142 ,

4th embodiment

In 7 an illumination source with an improved range is to be represented. To a far field chip 101 according to 7 to create an optical disc 102 increased in terms of their plate thickness. The mounting level of cathodic and anodic contacts 103 . 104 . 105 remains intact. Also a luminescent active layer 106 maintains its position in the anodically poled pillars. As a result of the envisaged and implemented increase in thickness of the optical disk 102 the distance increases 111 between the luminescent active layer 106 and the exit surface of the radiation from the chip body. To increase the concentration of radiation, the distance increases 111 the radius of curvature of the lens shape on the exit side also increased. In this way, the angular distribution of the luminescence can gradually increase from a wide lobe 108 to a narrower club 109 up to a pointed club 110 be focused.

Assists in increasing the thickness of the optical disc 102 solely on epitaxial coating processes, the effort for the production of the starting materials for the far field chips increases 101 too fast. It is therefore after 8 (a) and (B) proposed an optical disk designed according to the invention 121 with a pillar relief 122 on a free expandable expansion level 123 to be provided with an optical supplement. In doing so, become semiconductor supplementary wafers 124 with significantly different coefficients of thermal expansion, then there is a joining plane 125 on the supplementary disc 124 outside the optical section with blind holes 126 to provide. In the joining process of the known pane bond, the tension and curvature of the pane are reduced and the technological manufacturing process is not hindered. On the supplementary disc 124 there are already arched protrusions that act as concentrators 127 contribute to the bundling.

After 8 (b) can the supplementary disc 124 also with bundled optical fibers 128 be equipped.

The characteristics of an illumination source with a single luminescent pillar and a luminescent active layer made of Al _x Ga _1-x As with an x value of 0.29 ± 0.02 and an emission wavelength of 880 nm were examined depending on externally applied supply conditions. The forward DC current I _{F increases} after the diffusion voltage of about 1.2 V is exceeded in accordance with 9a strong. Despite the relatively broadband input material compared to silicon or other compound semiconductors and the lateral arrangement of the contacts, a surprisingly steep I _F -U _{F characteristic} curve arises: the low resistance of less than 2 ohms, which can be read from the increase, is the functionally adapted, highly conductive distribution layer of the charge carriers Kind of thanks.

The relationship between the radiation power P _opt (I _F ) and the flux current recorded at room temperature was determined for two differently advanced stages of the formation of the luminescent pillar and in 9b shown. With approximately the same diameter of the anodically poled pillar of D ≈ 250 μm, the pillar height L was varied. One time, L was only extended to the beginning of the distribution layer. In the second case, the pillar height L was increased by 250 μm by providing the distribution layer with the gradation described above. With a fixed forward current of I _F = 250 mA, the outcoupled radiation power of the chip, measured via the chip contacted on one side, with the graded distribution layer reaches an average value of 50 mW within the curve 151 , If the luminescence-active pillar ends at the beginning of the distribution layer, then the measured radiation power comes within the curve 150 with the same flow current only to 40 mW.

The chips used for this measurement can still be beneficial for one later in the embodiment 6 explained Use and enable final assembly so increased thermal loads.

5th embodiment

In this exemplary embodiment, the possibility of automatically checking the operation of the lighting source is described. For this purpose, the electrical wiring of the different pillars is modified with a similar chip layout and assigned with individually tailored operating potentials. 10 shows that the three diodes 163 . 165 and 167 forming pillars, which, like every diode, all contain a pn junction, for example have individual leads on the p-conducting side of the pn junction. In the first pillar (diode 163 ) is the pn junction, for example due to a small bridging resistance 162 shorted. The bridging creates the connection to an n-type distribution layer inside the chip by means of a vapor-deposited metal layer 164 , The ground potential 161 can be so or via a direct low-resistance connection to the distribution layer 164 and the remaining diodes 165 and 167 reach. The DH structure of the diode 165 receives through an individual contact 166 a pulsed or continuously equal supply voltage in the forward direction. The injection current flowing thereby, as described, calls the luminescence in the luminescence-active layer of the diode 165 out. The deflection on the lateral surface and the contact surface of the pillar leads the luminescence essentially in the direction of the exit surface.

After the publication of J.C. Campbell and A.G. Dentai in Applied Physics letters 41 (1982) 2 pp. 192-3 can be in InP / InGaAs heterojunction MESA phototransistors the light from a neighboring homojunction MESA LED made of InP looks good inject. This light influences a number of working parameters of the Phototransistor advantageous.

Deviating from this is now said to be in 10 while maintaining all structural properties in the layer structure of the circuit components only an internal monitoring function can be exercised by assigning different operating potentials.

Will the diode operated in the vicinity of the flow direction 165 located diode 167 through a contact 168 With a negative bias, the luminescence-active layer remains passive with regard to the emission. A photosensitive space charge zone is built up.

The direct transfer of the luminescence from the glowing diode 165 by air into the photosensitive zone of the diode 167 is only extremely small due to the selected conical pillar figures of the diodes.

However, part of the luminescence strikes the exit surface at an unfavorable angle and remains in the semiconductor body as a result of the total reflection and can be distributed over the optical disk. That from the neighboring diode 165 originating photons reach the diode 167 , As soon as they reach the space charge zone there, they are absorbed and converted into electron-hole pairs. The contact 168 outgoing reverse polarity creates an electric field in the DH structure that separates the charge carrier pairs. The current flowing thereby flows through the contact as reverse current 168 and depends reproducibly and linearly on the intensity of the on-chip luminescence. Even with a low coupling factor between the luminescence intensity of the luminescence active diode 165 and the photocurrent of the diode 167 Thanks to the linear relationship between luminescence and photocurrent, the luminescence intensity of the illumination source can be guided or tracked. As a result, the lighting source designed and operated in this way can be easily inserted into a conventional electrical control loop of the lighting intensity.

6th embodiment

In the last exemplary embodiment, a self-hermetic lighting source based on an 3 (b) explained chip structure, which is mounted on a heat-dissipating chip carrier. The chip structure there contained a closed, ring-shaped surrounding pillar 40 as external contact and four square pillars in the form of partial areas 36 - 39 in the central area. The contacts of the two types of pillars end in a common plane and are covered with a solderable surface. The square pillars in particular are equipped with cone-shaped lateral surfaces and serve to deflect the luminescence in the direction of the non-contact surface. That chip 200 is placed on a thermally conductive mounting pad 210 made of n-type silicon, see 11 (a) , Further details are shown in the section along the section line AA 'in 11 (b) , The assembly pad is to facilitate assembly 210 on their back 211 smooth and even and on their contact side 212 with recesses 213 provided according to the size of the central contact. The profiled contact page 212 is with a highly conductive, p-conductive layer 214 overdrawn. While the p-type layer 214 in the wells 213 is freely accessible, covers an insulating dielectric layer 215 , for example made of silicon oxide or silicon nitride, the flat regions of the profiled surface side. The free semiconductor area of the p-type layer 214 in the recess 213 is with solid metal pads 216 made of silver. These metal pads 216 can be by electroplating, for example after the DE 16 14 982 A faster and more adhesive than other methods. A thin solder deposit 217 on the metal cushion 216 creates the conditions for a mechanical, electrical and heat-dissipating connection between the central sub-areas 36 - 39 and the metal cushion 216 , On the outer edge of the assembly pad 210 is the dielectric layer 215 locally removed again and access to the p-type layer 214 exposed. About a bond island 218 can the p-type layer 214 be connected to the operating voltage of the lighting source. The second connection is made via a strip conductor deposited on the insulating layer 219 , He is also with a thin solder deposit 217 occupies and establishes the connection to the ring-shaped surrounding pillar 40 of the luminescence chip. The stripline 219 for the external contacts of the self-hermetic luminescence chips are line by line up to the edge of the mounting pad 210 pulled and form a connection field there 220 for the second connection terminal. About the number of luminescence chips used on the assembly pad 210 the achievable overall intensity can be adapted to the needs in the application situation. The solder connection between the external contacts of the individual chips and the adequately designed annular zones of the strip conductors 219 on the assembly pad 210 separates the micro atmosphere around the metal cushion 216 and the outer surface of the luminescent pillar is permanently hermetically sealed from the outside atmosphere. The entire lighting source after 11 (a) can therefore be used without additional capping. Lighting sources that are to be used in aggressive environments must be chemically impregnated beforehand.

The chips of the lighting source can be electric both individually X-Y addressed or as a closed cluster field to be activated.

1

LED-Chip

2

n-leitende Schicht

3

p-leitende Schicht

4

Grube

4a

erste Seitenwand (der Grube)

4b

zweite Seitenwand (der Grube)

4c

Boden der Grube

5

Oberfläche (der p- Schicht)

6

n-Kontakt

7

p-Kontakt

8

Maske (aus Dielektrikum-Material)

9

Linse

10

Oberfläche der n- Schicht

11

pn-Übergangsfläche

12a, 12b

dünne Metallflächen

13, 14

Bondinsel

2 (State of the art)

1

LED chip

2

n-type layer

3

p-type layer

4

pit

4a

first side wall (the pit)

4b

second side wall (the pit)

4c

Bottom of the pit

5

Surface (of the p-layer)

6

n-contact

7

p-contact

8th

Mask (made of dielectric material)

9

lens

10

Surface of the n-layer

11

pn junction surface

12a, 12b

thin metal surfaces

13, 14

Bond island

1

20

optical plate

21

(Lumineszenzaktive) pn junctions

22

(Lumineszenzaktive) pn junctions

23

(Lumineszenzaktive) pn junctions

24

anode contacts

25

anode contacts

26

anode contacts

27

n-type distribution layer

28

Contact (poled cathodically)

29

crystallographically oriented bevel

3 (b)

30

optical plate

31

pier

(anodic poled)

32

pier

(anodic poled)

33

pier

(anodic poled)

34

pier (poled cathodically)

35

optische Platte

36, 37, 38, 39

Teilflächen (der Emissionsfläche)

40

Umfassungspfeiler

(ringförmig, kathodisch polbar)

3 (b) . (C)

35

optical disc

36, 37, 38, 39

Partial areas (of the emission area)

40

Umfassungspfeiler

(ring-shaped, cathodically polarizable)

4 (A)

51

(incomplete) chip structure

52

pier

(cathodic poled)

53 54

pier

(anodic poled)

55

lumineszenzaktive layer

56

distribution layer

57

accepted reference point

58 59

Rays (from the semi-cone 60 )

60

Half-cones, reflects on embankment

61

Half-cones, unthinkingly

62a-d

Rays (from the semi-cone 61 )

63

(Continued guided) beam

4 (B)

71

chip structure

72

pier (poled cathodically)

73.74

pier (anodically poled)

75

lumineszenzaktive layer

distribution layer

77

reference point

78.79

marginal rays

80

radiation cone

5 (A)

41

trapezoidal projection

42

distribution layer

43

non-luminescent pillar

44

cathode contact

44a

Leitbahntrasse

44b

collar

45

(luminescent) layer

46

anode contact

5 (B)

91

pier

(cathodic poled)

92

(N-type) distribution layer

93

cathode contact

94

Leitbahntrasse

95

lumineszenzaktive layer

96

P-type cladding layer

97

(P-type) Bragg reflector

98

pier (anodically poled)

99

anode contact

100

Antireflection coating

6

131.132

solder

133

silicon case

134

mounting tray

135

inner wall (the assembly tub)

136 137

Conductor tracks (to chip contacts)

138

via

139

external connection (the anode)

140

external connection (the cathode)

141

sealing plate

142

(Imaging) bulge

7

101

Far-field chip

102

optical plate

103

(Cathodic) Contact

104

anodic Contact

105

anodic Contact

106

lumineszenzaktive layer

107

convex head Start

108 109, 110

mace

111

distance

121

optische Platte

122

Pfeilerrelief

123

Erweiterbare Ausbauebene

124

Ergänzungsscheibe

125

Fügeebene

126

Aussparung

127

Konzentratoren

128

Lichtleitfaser

8 (a) and (B)

121

optical disc

122

pillars relief

123

Expandable expansion level

124

Supplementary disc

125

joining plane

126

recess

127

concentrators

128

optical fiber

9 b

150

P _opt (I _F ) at room temperature without

151

P _opt (I _F ) at room temperature with

segmented emitting surface

10

160

chip structure

161

ground potential

162

shunt resistor

163

diode

164

distribution layer

165

diode

166

Contact

167

diode

168

Contact

200

Chip

210

Montageunterlage

211

Rückseite

212

Kontaktseite

213

Vertiefungen

214

p-leitende Schicht

215

dielektrische Schicht

216

Metallpolster

217

dünnes Lotdepot

218

Bondinsel

219

Streifenleiter

220

Anschlussfeld

L

Pfeilerhöhe

D

Distanz (Diagonale)

S_o

optische Sektion

11 (a) and (B)

200

chip

210

Mounting pad

211

back

212

Contact

213

wells

214

p-type layer

215

dielectric layer

216

metal pads

217

thin solder deposit

218

Bond island

219

stripline

220

connection panel

L

pier height

D

Distance (diagonal)

S _o

optical section

Claims (14)

Bipolar illumination source made of a self-bundling semiconductor body contacted on one side, the substrate of which is transparent to the luminescence waves and connected to a structure of layers of ternary and binary III-V connections and which is set up for pseudo-lateral operation, with a mechanical bridge made of an optical plate ( 20 . 30 . 35 . 102 ) from a semiconductor body uniformly transparent for luminescence, with which at least two luminescent pillars and exactly one assigned non-luminescent pillar ( 31-33 . 36-39 . 73-74 . 98 ; 34 . 40 . 43 . 72 . 91 ) are kept next to each other at a desired distance, the luminescent pillars ( 31-33 . 36-39 . 73-74 . 98 ) a layer structure and a luminescence-active layer ( 45 . 75 . 95 . 106 ) and with a smaller cross-section than the non-luminescent pillar ( 34 . 40 . 43 . 72 . 91 ) are formed, all pillars ( 31-33 . 36-39 . 73-74 . 98 ; 34 . 40 . 43 . 72 . 91 ) end on the underside in the same level in a flat mounting surface, the pillars ( 31-33 . 36-39 . 73-74 . 98 ; 34 . 40 . 43 . 72 . 91 ) towards the optical disc ( 20 . 30 . 35 . 102 ) continuously expand conically in terms of their cross-section and into a continuous, transparent, uniformly conductive, highly conductive distributor layer ( 27 . 42 . 76 . 92 ) to supply the luminescence-active layer ( 45 . 75 . 95 . 106 ) with charge carriers of a first type from a first electrode ( 24-26 . 46 . 99 ) pass over and this distribution layer ( 27 . 42 . 76 . 92 ) via a metallic interconnect ( 44a . 94 ) along the slope of the lateral surface of the non-luminescent pillar ( 34 . 40 . 43 . 72 . 91 ) with his contact ( 28 . 44 . 93 ) is connected to the mounting surface, each luminescent pillar ( 31-33 . 36-39 . 73-74 . 98 ) on its assigned mounting surface with an oppositely polarized contact electrode ( 24-26 . 46 . 99 ) for the supply of load carriers second type is provided, and the adjacent mounting surfaces are provided with the same metal coating for simultaneous and identical insertion into a supply or control circuit. Bipolar illumination source according to claim 1, characterized in that the luminescent pillars ( 31 - 33 . 36 - 39 . 73 - 74 . 98 ) in a line, in the corners or centrally symmetrical in the center on the optical plate ( 20 . 30 . 35 . 102 ) are arranged and have an angular, round or crescent-shaped pillar cross-section. Bipolar illumination source according to claim 1 or 2, characterized in that the non-luminescent pillar ( 34 . 40 . 43 . 72 . 91 ) as an extended bar, as a square in a corner or in a ring or frame shape next to and around the luminescent pillars ( 31 - 33 . 36 - 39 . 73 - 74 . 98 ) around on the optical disc ( 20 . 30 . 35 . 102 ) is arranged. Bipolar illumination source according to one of the preceding claims, characterized in that the horizontal position of the distribution layer ( 42 . 92 ) is provided with gradations such that the distribution layer ( 42 . 92 ) at least over the luminescent pillars ( 31 - 33 . 36 - 39 . 73 - 74 . 98 ) via trapezoidal projections ( 41 ) is spread out and has a uniform layer thickness of 5-25 μm, preferably 15 μm. Bipolar illumination source according to one of the preceding claims, characterized in that the entire luminescence-active area consists of an appropriate number of luminescence-capable pillars ( 31 - 33 . 36 - 39 . 73-74 . 98 ) is formed, each of these pillars ( 31 - 33 . 36 - 39 . 73 - 74 . 98 ) close to the non-luminescent pillar ( 34 . 40 . 43 . 72 . 91 ) is arranged. Bipolar illumination source according to one of the preceding claims, characterized in that the pillar dimensioning in the luminescent pillars ( 31 - 33 . 36 - 39 . 73 - 74 . 98 ) a height L of the relationship based on their diagonal D. L = F (θ crit (n) , D) = D tan θ crit / (1 + 2tan θ crit ) (1) follows and a cone-like shape is used to deflect the luminescence. Bipolar illumination source according to one of the preceding claims, characterized in that the metallic conductor track ( 44a . 94 ) on the inclined surface of the non-luminescent pillar ( 43 . 91 ) is covered with a solder mask. Bipolar illumination source according to one of the preceding claims, characterized in that an arrangement of imaging elements ( 107 . 124 . 142 ) is designed to concentrate the radiation. Bipolar illumination source according to one of claims 1 to 7, characterized in that a lens plate ( 124 ) cannot be detached from the optical plate ( 121 ) is attached, which also remains attached to each individual chip during the separation and assembly process and the bundling of the radiation from the luminescent pillars involved ( 31 - 33 . 36 - 39 . 73 - 74 . 98 ) brings about. Bipolar illumination source according to one of Claims 1 to 7, characterized in that the optical plate ( 121 ) one on the distribution of the luminescent pillars ( 31 - 33 . 36 - 39 . 73 - 74 . 98 ) cut optical fiber plate ( 128 ) is permanently attached, which bundles the radiation. Bipolar illumination source according to one of the preceding claims, characterized in that one of the luminescent pillars ( 31 - 33 . 36 - 39 . 73 - 74 . 98 ) contacted individually and temporarily or continuously in the reverse direction like a photodiode ( 168 ) is operable and that at the contact of this pillar ( 31 - 33 . 36 - 39 . 73 - 74 . 98 ) removable photocurrent to measure the height of the remaining pillars ( 165 ) is made impulsively or continuously to be impressed electrical flow current. Bipolar illumination source according to one of the preceding claims, characterized in that a coherent, ring-shaped or frame-shaped pillar structure ( 40 ) which are the luminescent pillars ( 36-39 ) surrounds a sealing zone for the hermetic connection between the individual chip ( 200 ) and an assembly document ( 210 ) forms a permanent mechanical and electrical connection between the frame contact on the pillar structure using a solder or a conductive adhesive ( 40 ) and the adequate ring zones of a stripline ( 219 ) the assembly document ( 210 ) is brought about. Bipolar illumination source according to one of the preceding claims, characterized in that an assembly base ( 210 ) wells at the chip receiving points ( 213 ) with massive silver cushions ( 216 ) are filled and a thermal and electrical connection to the luminescent pillars ( 36 - 39 ) produce. Bipolar illumination source according to one of claims 12 or 13, characterized in that the mounting base ( 210 ) consists of n-type silicon and on the contact side of parallel arranged p-type layers following the surface profile of the silicon ( 214 ) covered on a bond island ( 218 ) can be connected to the operating voltage.