DE10329365A1 - Radiation-emitting semiconductor chip comprises a brightness adjusting layer arranged consisting of an electrically insulating current blocking region and an electrically conducting current passage region - Google Patents

Abstract

Radiation-emitting semiconductor chip (1) comprises a brightness adjusting layer arranged between a connecting region (4) and an active layer and consists of an electrically insulating current blocking region (62) and an electrically conducting current passage region (61) via which the connecting region is electrically connected to a semiconductor layer sequence. A part of the electromagnetic radiation produced in the chip is produced below the connecting region and is absorbed by it. An independent claim is also included for a process for the production of a radiation-emitting semiconductor chip.

Description

The The invention relates to a radiation-emitting semiconductor chip with a semiconductor layer sequence, the at least one an electromagnetic Radiation-generating active layer comprises, and with an electrical Contact layer, which has a connection area and an outside of the connection area arranged and electrically connected to this Strominjektionsbereich includes. It further relates to a method for producing such Semiconductor chips.

The Semiconductor layers of semiconductor chips, for example, the radiation-generating layer structures of radiation-emitting and radiation-receiving semiconductor chips can through a variety of different epitaxy methods, such as organometallic Vapor phase epitaxy (Metal Organ Vapor Phase Epitaxy (MOVPE), Molecular Beam Epitaxy (MBE), liquid phase epitaxy (Liquid Phase Epitaxy (LPE), etc. Alternatively or additional can such layer structures at least partially by diffusion be defined by dopants.

Either Epitaxy processes as well as doping processes are subject to certain manufacturing variations. In light-emitting semiconductor chips lead manufacturing fluctuations often to fluctuations in the brightness of nominally identical semiconductor chips operational. Both those produced in different epitaxy process runs Wafer, as well as the same time produced in a single process run Wafers are subject to manufacturing fluctuations, with fluctuations within in a process run produced wafers are smaller.

Of the Invention is based on the object, a semiconductor chip structure indicate their radiation emission during their production a desired range is adjustable.

A It is still a task, a method for producing such Semiconductor chips available to deliver.

These Tasks are performed by a semiconductor chip with the characteristics of Claim 1 and by a method having the features of the claim 11 solved.

The Brightness adjustment layer allows it also, from wafers with different brightness, like them for example due to variations in the epitaxial and / or doping process or due to Variations between different process cycles can arise, semiconductor chips produce their brightness comparatively safe within a predetermined desired brightness range

Farther allows it is a semiconductor chip structure according to the invention advantageously, with similarly epitaxierten semiconductor layer sequences semiconductor chips with, for example, application-dependent specifically to produce different brightnesses. It is therefore advantageously no longer consistently required for the production different from semiconductor chips with different brightnesses To use epitaxial processes.

A Epitaxieanlage can therefore with advantage to an increased extent with consistent process sequences operating altogether, resulting in an overall stabilization of epitaxy processes contributes.

Around To set chip batches within the target brightness range, it is appropriate, rather very produce bright chips, which then ge after completion of the Halbleiterschichtenfol through the brightness adjustment layer to a depending on the application desired uniform level be darkened.

advantageous embodiments and further developments of the semiconductor chip and the method for production Such a semiconductor chip are in the dependent claims 2 to 9 and 12 and 13 indicated.

One Semiconductor chip according to the invention contains a semiconductor layer sequence, the at least one electromagnetic Radiation-generating active layer contains and on the one electrically conductive Contact layer is applied, which has a terminal area and, spatially separated therefrom, comprises a current injection area. Between terminal region and active layer, a brightness adjustment layer is arranged, the at least one electrically insulating current blocking region and at least one electrically conductive Stromdurchlaßbereich includes. The current passage area connects the connection area and the semiconductor layer sequence in such an electrically conductive manner with one another, that in the Operation of the semiconductor chip Current under the connection area is injected into the semiconductor layer sequence. Part of the Chip generated electromagnetic radiation is under the connection area generated and absorbed by this.

In the present case, the indication that the brightness adjusting layer is arranged between the terminal region and the active layer means the case where the brightness adjusting layer and the terminal region are viewed from the active layer at least partially overlap. For example, they overlap such that the terminal region completely covers the brightness adjusting layer.

Especially preferred are the size and the location of the current passage area set such that a Operating current of the semiconductor chip to such a proportion below the connection part is injected and therefore correspond to the absorption of im Semiconductor chip generated radiation in the connection area leads that a radiation emission of the Semiconductor chips within a predetermined target range is.

means the current passage area targeted electromagnetic radiation is generated in the semiconductor chip, not decoupled from this, but in the contact layer is absorbed. About this Path can, for example, semiconductor chips whose semiconductor layer sequence has a brightness that is above one at a fixed Operating current desired Target range, the brightness of the chip can be reduced by a part of the fixed operating current below the connection area injected and at least a portion of the radiation generated there from terminal region is absorbed. By adjusting the size and location of the current passage area For example, the proportion of radiation generated in the semiconductor chip that originates from this not decoupled, be set. In a semiconductor layer sequence for example, with comparatively low brightness to achieve the same brightness with the chips as with chips one with the same operating current "brighter" semiconductor layer sequence, the Stromdurchlaßbereich across from the chip with a "brighter" semiconductor layer sequence designed smaller.

precautionary It should be noted that "brightness" is not present exclusively but on visible light emitting semiconductor layers also on infrared radiation and / or on UV radiation emitting Semiconductor layers sequences. Consequently, the invention is not limited to visible light emitting semiconductor chips, but also refers to IR-emitting semiconductor chips as well UV-emitting semiconductor chips.

Inventive semiconductor chips can do that be prepared that despite Fluctuations in the epitaxy and / or doping process Semiconductor chips achieved who the who within a target brightness range lie.

Under Application of chip structures and methods according to the present invention is it to uniform chip brightness batches in one or more process runs to achieve, particularly useful, semiconductor layer sequences with compared to the target brightness range of the finished chips of greater brightness to manufacture, and the chip brightness by means of a brightness adjustment layer according to the invention to set, that is to darken.

In a preferred embodiment contains the current blocking layer silicon nitride. A current blocking layer can by various methods, for example by sputtering or Vapor deposition, be applied.

Of the Current blocking area includes appropriate one on the semiconductor layer sequence applied electrically insulating Layer with a recess, and the connection area is in the recess applied to the semiconductor layer sequence.

The Recess in the current blocking area, for example, after application an electrical insulation layer by a conventional method, like etching or sputtering be introduced. The recess can already during the application the insulating layer introduced by means of lithographic methods be. By example, conventional Applying the contact layer fills the contact layer is the recess and is thus in physical Contact with the semiconductor layer sequence.

at another advantageous embodiment The current blocking area is between active layer and terminal area arranged electrically insulating region of the semiconductor layer sequence. This may appropriate the Current blocking region a proton-implanted region of the semiconductor layer sequence and the current passage area a region of the semiconductor layer sequence with a lower contrast Be proton concentration.

Preferably is a transverse conductivity in the semiconductor layer sequence so low that in operation of the semiconductor chip current, which under the terminal region in the semiconductor layer sequence is injected, essentially to the coverage area of terminal area and semiconductor layer sequence remains limited.

This contributes significantly to help that a radiation generation through under the connection area Current injection over the connection area the desired Reduction in brightness of the semiconductor chips result.

Prefers the chip structure according to the invention is suitable for semiconductor chips with a semiconductor layer sequence based on InGaAlP.

In the present case, the group of radiation-emitting and / or radiation-detecting chips based on InGaAlP falls in particular Such chips in which the epitaxially produced semiconductor layer sequence, which as a rule has a layer sequence of different individual layers, contains at least one single layer comprising a material of the III-V compound semiconductor material system In _x Al _y Ga _1-xy P with 0 ≦ x ≦ 1, 0 ≦ y ≦ 1 and x + y ≦ 1. The semiconductor layer sequence can, for example, have a conventional pn junction, a double heterostructure, a single quantum well structure (SQW structure) or a multiple quantum well structure (MQW structure). Such structures are known to the person skilled in the art and are therefore not explained in detail at this point. In principle, a semiconductor chip according to the invention can be based on any semiconductor material that can be used for radiation-emitting and / or -receiving chips.

In an advantageous embodiment of the semiconductor chip, the insulating layer is at least partially arranged between current injection region and semiconductor layer sequence. With this variant, the outside of the connection area injected portion of the operating current can be reduced.

According to the invention can in a semiconductor layer sequence with one above or below a setpoint lying radiant power the size and the position of the Stromdurchlaßbereichs and the current blocking region are selected such that an operating current of the semiconductor chip is injected to such a portion under the terminal part and thus to a corresponding absorption in the semiconductor chip generated radiation in the connection area leads that a radiation emission of the semiconductor chip is within a predetermined desired range.

The Brightness adjustment layer can instead of having a current blocking area and a current passage area alternatively with the help of a between terminal area and active layer arranged through a continuous electrically conductive layer can be realized their electrical resistance depends on the brightness of the Semiconductor layer sequence is set.

A additional or alternative way a part of a radiation generated excessively in the semiconductor chip to Brightness adjustment by shading "hide", is the width of connecting webs between the connection area and to broaden the current injection area. This is optional for themselves alone a possibility but to achieve a sufficient brightness control, but can also in addition be used for the above-described technical means.

at a method of manufacturing a semiconductor chip according to the invention is after making or during producing the semiconductor layer sequence with an active layer measured on a substrate, the brightness of the semiconductor layer sequence. Subsequently, on the basis of the measurement result, a suitable Determines the geometry of the brightness adjustment layer and the brightness adjustment layer formed according to the semiconductor layer sequence. following becomes the contact layer with terminal area and current injection area educated.

at a convenient procedure This type is after measuring the semiconductor layer sequence and forming an electrically insulating layer as the current blocking region with a recess for the current passage area the contact layer is applied while the recess at least partially filled with contact layer material.

at another appropriate embodiment of the method becomes after measuring the semiconductor layer sequence the current passage area and the current blocking region by different doping of a near-surface Area of the semiconductor layer sequence generated.

Independently of, where are the current blocking region and the current passage region can, can Shape and size of the contact layer always unchanged stay. The structure of the semiconductor chips in plan view can therefore advantageously remain essentially unchanged, which is automatic Image recognition in production machines, such as die bonders, and especially for measuring equipment beneficial effect.

The fundamental Principle of the present invention is the brightness of radiation-emitting semiconductor chips, that advantageously while manufacturing the semiconductor chips after measuring radiation emission characteristics a radiation-emitting semiconductor layer sequence of a wafer a brightness adjusting layer on a radiation outcoupling side of the wafer is applied.

Further advantages, advantageous embodiments and developments will become apparent from the following in connection with in 1 . 2 . 3a - 3d . 4a - 4d . 5 and 6 explained embodiments. Show it:

1 FIG. 2 a schematic illustration of a top view of a semiconductor chip according to a first exemplary embodiment, FIG.

2 a schematic representation of a Section through the first embodiment,

3a - 3d schematic representations of plan views of four variants of the first embodiment,

4a - 4d schematic representations of plan views of four further variants of the first embodiment,

5 a schematic representation of a section through a second embodiment,

6 a schematic representation of a section through a third embodiment.

In the various embodiments are the same or equivalent components each referred to the same and provided with the same reference numerals. The illustrated layer thicknesses are not as true to scale to watch. They are rather exaggerated for better understanding and not with the actual Thickness ratios to each other shown.

In the embodiment, as in the 1 and 2 is shown, it is a radiation-emitting semiconductor chip 1 with an InGaAlP-based semiconductor layer sequence 3 , which is an electromagnetic radiation generating active layer 2 having. This active layer 2 may consist of a single semiconductor layer or comprise a plurality of semiconductor layers forming, for example, a multi-quantum well structure.

On the semiconductor layer sequence 3 is a contact layer 7 with a connection area 4 and a current injection area 5 applied. The connection area 4 is a circular bond pad that sits in the middle of a square frame that defines the current injection area 5 represents arranged. Both the connection area 4 as well as the current injection area 5 can have different geometries as needed.

Between the connection area 4 and the semiconductor layer sequence 3 is a brightness adjustment layer 6 arranged, consisting of a centrally located below the terminal area current passage area 61 and one the current passage area 61 ring-like surrounding current blocking area 62 composed.

The current blocking area 62 For example, it may be a silicon nitride layer. The current blocking area 62 but may also be made of other electrically insulating materials conventionally used in semiconductor technology. In the operation of the semiconductor chip, power is supplied exclusively via the current injection region 5 and through the current passage area 61 in the semiconductor layer sequence 3 and thus into the active layer 2 injected.

The current injection over the current passage area 61 the brightness adjustment layer 6 causes a portion of a given operating current in the active layer 2 Radiation generated, which is not decoupled from the semiconductor chip to a significant extent, but is absorbed by the terminal area. About the size of the current passage area 61 The amount of radiation that is not decoupled can be adjusted. To a corresponding extent, the current injection current is kept lower than the current injection range 5 injected current and consequently through it in the active layer 2 generated radiation which is decoupled from the semiconductor chip.

If necessary for sufficient brightness reduction, the current blocking region may also be at least partially between the current injection region 5 and the active layer 2 be arranged. The operating current can then for example, to a large extent or in total over the terminal area 4 into the active layer 2 be injected.

Regardless of where the current blocking area 62 can, shape and size of the contact layer 7 remain unchanged. The semiconductor chips 1 Therefore, they remain essentially the same in their plan view, which, as already stated above, is advantageous for automatic image recognition in various production machines, such as die bonders, and for measuring devices.

The four variants of semiconductor chips according to the 3a ) to 3d ) have with respect to the above in connection with the 1 and 2 described embodiment differently sized Stromdurchlaßöffnungen 61 on. The size of the current passage area 61 takes from the variant according to 3a ) to the variant according to 3d ) in each case too. If the semiconductor layer sequences of all four variants have the same radiation properties and if all four variants are operated with the same operating current, then the brightness of the semiconductor chips increases according to the variant 3a ) to the variant according to 3d ) from each, because of 3a ) to 3d ) becomes an ever greater proportion of the operating current below the terminal area 4 injected. Due to the transverse conductivity of the semiconductor layer sequence 3 There may be a current widening below the Stromdurchlaßbereiches 61 come. Therefore, also the under the connection area 4 injected electricity partially contribute to the decoupled radiation. The farther the point of current injection over the current passing area but not from the terminal area 4 covered area of the radiation decoupling surface 10 is removed, the less can the under the connection area 4 generated radiation contribute to the radiation emission. Accordingly, in the in the 3a ) to 3d ) shown Stromdurchlaßbereichen 61 in the order of 3a ) to 3d ) injected more power because of their growing areas, on the other hand, because of the growing proximity to the radiation decoupling surface 10 a larger proportion of under the connection area 4 generated radiation decoupled. Which of these two opposing effects dominates depends essentially on the current spreading properties of the semiconductor layer sequence 3 from. For an effective brightness reduction with the help of the current passage area 61 it makes sense that also in the variant according to 3d ) only a little of that under the connection area 4 injected current can generate radiation that is coupled out of the chip and thus to the brightness of the semiconductor chip 1 can contribute. However, there may be other reasons that require better current spreading, such as reducing the current density below the current injection range 5 , Depending on the particular requirement, the brightness adjusting layer must be adjusted.

In the four variants of semiconductor chips according to the 4a ) to d) is the current blocking area 62 the brightness adjustment layer 6 below the current injection range 5 pulled, so that the current injection into the semiconductor layer sequence 3 exclusively over the current passage area 61 the brightness adjustment layer 6 under the connection area 4 the contact layer 7 can be done. The brightness of a semiconductor chip 1 according to 4b ) substantially corresponds to that of a semiconductor chip 1 which has only one bonding pad directly on the semiconductor layer sequence. According to the semiconductor chip 4a ) is the current passage area 61 ring-shaped and below the terminal area 4 arranged. Such a semiconductor chip 1 is brighter than a semiconductor chip according to the variant of FIG 4b ), because more current at the edge of the terminal area 4 and thus close to the radiation decoupling surface 10 of the semiconductor chip is injected. The variant according to 4c ) points below the connection area 4 a central first flow passage area 611 and a second current passage region extending annularly around it 612 on. The variant according to 4d ) points below the connection area 4 only a relatively small central Stromdurchlaßbereich 61 on. The brightnesses of the semiconductor chips according to the 4c ) and 4d ), identical semiconductor layer sequences as provided in the previous variants, less than the brightnesses of the semiconductor chips according to the 4a ) and 4b ), since the current injection into the semiconductor layer sequence and thus the generation of radiation in the semiconductor layer sequence are for the most part comparatively far away from the radiation coupling-out surface 10 he follows.

In a second embodiment, as in 5 As an alternative to the embodiment described above and its variants, the current blocking region is an electrically insulating region of the semiconductor layer sequence arranged between the active layer and the connection region. In this case, the current blocking region can expediently be a proton-implanted region of the semiconductor layer sequence and the current-passing region can be an area of the semiconductor layer sequence with a comparatively lower proton concentration. The principal two-dimensional geometry of the brightness adjustment layer in plan view can be chosen according to the embodiment described above and its variants.

In a third embodiment according to 6 is the brightness adjusting layer instead of having a current blocking area and a current passing area by means of an between terminal area 4 and active layer 2 arranged continuous electrically conductive layer 19 realized whose electrical resistance depends on the desired brightness of the semiconductor layer sequence 3 is set.

In yet another embodiment, in addition to or as an alternative to the above-mentioned brightness adjusting means for adjusting the brightness, there are connecting webs between the terminal area 4 and the current injection area 5 widened.

In one exemplary embodiment of a method according to the invention, after the manufacture or during the production of the semiconductor layer sequence 3 with an active layer 2 on a substrate, the brightness of the semiconductor layer sequence 3 measured. Hereinafter, on the basis of the measurement result, a suitable geometry of the brightness adjustment layer will be determined 6 and the brightness adjustment layer 6 corresponding to the semiconductor layer sequence 3 educated. The following is the contact layer 7 with connection area 4 and current injection area 5 , which has conductive webs with the connection area 4 is electrically connected, formed. This is done after measuring the semiconductor layer sequence 3 and forming an electrically insulating layer as the current blocking region 62 with a recess for the current passage area 61 the contact layer 7 applied while the recess at least partially filled with contact layer material. Alternatively, after measuring the semiconductor layer sequence, the current passage region 61 and the current blocking area 62 by different doping of a near-surface region of the semiconductor layer sequence 3 subsequently generates the contact layer 7 be applied.

Of course, the invention is not up the embodiments described concretely limited, but extends to all devices and methods having the basic features of the invention. In particular, radiation-emitting semiconductor chips of different geometry and different structures can be used. In addition, the semiconductor layer sequences can follow 3 be constructed of different material systems, such as GaN-based or GaAs-based semiconductor material.

Claims (13)

Radiation-emitting semiconductor chip ( 1 ) with a semiconductor layer sequence ( 3 ) which comprises at least one active-layer electromagnetic radiation generating layer ( 2 ) and with an electrical contact layer ( 7 ), which has a connection area ( 4 ) and an outside of the terminal region arranged and electrically connected to the terminal region Strominjektionsbereich ( 5 ), characterized in that between the terminal area ( 4 ) and the active layer ( 2 ) a brightness adjustment layer ( 6 ) is arranged, the at least one electrically insulating current blocking region ( 62 ) and at least one electrically conductive current passage region ( 61 ), over which the connection area ( 4 ) with the semiconductor layer sequence ( 3 ) is electrically conductively connected, such that during operation of the semiconductor chip ( 1 ) a portion of the electromagnetic radiation generated in the chip under the terminal region ( 4 ) is generated and absorbed by this. Semiconductor chip according to Claim 1, characterized in that the size and the position of the current passage region ( 61 ) are selected such that an operating current of the semiconductor chip to such a portion under the connecting part ( 4 ) and thus results in a corresponding absorption of radiation generated in the semiconductor chip in the connection region that a radiation emission of the semiconductor chip is within a predetermined desired range. Semiconductor chip according to Claim 1 or 2, characterized in that the current blocking region ( 62 ) Contains silicon nitride. Semiconductor chip according to one of Claims 1 to 3, characterized in that the current blocking region ( 62 ) one on the semiconductor layer sequence ( 3 ) comprises an electrically insulating layer with a recess and the connection region within the recess on the semiconductor layer sequence ( 3 ) is applied. Semiconductor chip according to one of Claims 1 to 3, characterized in that the current blocking region ( 62 ) between active layer ( 2 ) and connection area ( 4 ) arranged electrically insulating region of the semiconductor layer sequence ( 3 ). Semiconductor chip according to Claim 5, characterized in that the current blocking region ( 62 ) a proton-implanted region of the semiconductor layer sequence ( 3 ). Semiconductor chip according to Claim 6, characterized in that the current-passing region ( 61 ) an area of the semiconductor layer sequence ( 3 ) with a lower proton concentration than in the current blocking region ( 62 ). Semiconductor chip according to one of Claims 1 to 7, characterized in that a transverse conductivity in the semiconductor layer sequence ( 3 ) is so small that during operation of the semiconductor chip ( 1 ) Electricity flowing under the connection area ( 4 ) in the semiconductor layer sequence ( 3 ), substantially to an area below the terminal area ( 4 ) remains limited. Semiconductor chip according to one of Claims 1 to 8, characterized in that the semiconductor layer sequence ( 3 ) based on InGaAlP. Semiconductor chip according to one of Claims 1 to 9, characterized in that at least partially between current injection region ( 5 ) and semiconductor layer sequence ( 3 ) an electrically insulating layer ( 9 ) is arranged. Method for producing a semiconductor chip according to at least one of Claims 1 to 10, characterized by the method steps: - producing the semiconductor layer sequence ( 3 ) with an active layer ( 2 ) on a substrate; Measuring radiation emission properties of the semiconductor layer sequence; Determining a suitable geometry of the brightness adjustment layer; Forming the brightness adjustment layer ( 6 ); Application of the contact layer ( 7 ) with connection area ( 4 ) and current injection area ( 5 ). Method according to claim 11 with reference to claim 4 or to one of the claims dependent on claim 4, characterized in that after measuring the semiconductor layer sequence ( 3 ) and training. the electrically insulating layer as the current blocking region ( 62 ) with a recess for the current passage area ( 61 ) the contact layer ( 7 ) is applied and while the recess is at least partially filled with contact layer material. The method of claim 11 with reference back to claim 5 or to one of the claims back to claim 5, characterized gekenn characterized in that the current passage region ( 61 ) and the current blocking area ( 62 ) by different doping of a near-surface region of the semiconductor layer sequence ( 3 ) be generated.