WO2017129481A1

WO2017129481A1 - Substrate with structural elements and semi-conductor components

Info

Publication number: WO2017129481A1
Application number: PCT/EP2017/051154
Authority: WO
Inventors: Tobias Gotschke; Werner Bergbauer; Thomas LEHNHARDT; Lorenzo Zini; Philipp Drechsel
Original assignee: Osram Opto Semiconductors Gmbh
Priority date: 2016-01-25
Filing date: 2017-01-20
Publication date: 2017-08-03
Also published as: TW201801347A; DE102016200953A1

Abstract

The invention relates to a substrate (1) with a separation side (10) and a rear side (11) which is opposite the separation side. A plurality of structural elements (2) are arranged on the separation side and the structural elements are arranged such that they form a plurality of grouped areas (4) each having respectively at least two structural elements.

Description

description

SUBSTRATE WITH STRUCTURAL ELEMENTS AND SEMICONDUCTOR ELEMENT

The present application relates to a substrate with

Structural elements and a semiconductor device with such a substrate.

For the epitaxial deposition of nitridic

Compound semiconductor material can be applied to structured sapphire substrates in which structures are distributed uniformly over the surface of the substrates. By a lateral overgrowth of such structures in the micrometer range, a Defektreduktion of the material to be deposited can be achieved. In light-emitting diodes with these substrates, the structures also provide an improved

Decoupling efficiency compared to planar substrates.

Furthermore, structures in the nanometer range are known. With such substrates, a comparable Auskoppeleffizienz can be achieved. However, a significantly lower defect reduction takes place.

An object is to facilitate the production of light emitting diodes with a high crystal quality and at the same time with a good coupling-out efficiency.

This object is achieved inter alia by a substrate according to claim 1 or by a

Semiconductor device solved with such a substrate.

Further embodiments and expediencies are the subject of the dependent claims. It is a substrate with a separation side and a deposition side opposite back given. The separation side is especially for the epitaxial

Deposition of semiconductor material provided based on nitridic compound semiconductor material. For example, the substrate has a substrate body. The substrate body contains, for example, sapphire or consists of sapphire.

For example, the substrate body forms the separation side. Alternatively, the separation side by means of a on the

Substrate body arranged layer formed.

Based on "nitride compound semiconductor material" in the present context means that

Semiconductor layer sequence or at least a part thereof, particularly preferably at least the active region and / or the growth substrate, a nitride compound semiconductor material, preferably Al _x In _y Gai- _x - _y N or consists of this, wherein O ^ x ^ l, O ^ y ^ l and x + y -S 1. This material does not necessarily have to be mathematically exact

Having composition according to the above formula. Rather, it may, for example, one or more dopants as well

have additional ingredients. For the sake of simplicity, however, the above formula includes only the essential ones

Components of the crystal lattice (Al, Ga, In, N), even if these can be partially replaced by small amounts of other substances and / or supplemented.

In accordance with at least one embodiment of the substrate, a plurality of structural elements is arranged on the deposition side. The structural elements are in particular in

laterally arranged side by side and at least in places spaced from each other. For example, the structural elements are designed such that a Nucleation probability in the epitaxial

Deposition on the structural elements is less than in an area between the structural elements. The lateral direction is considered to be a direction along a main plane of extension of the substrate. Accordingly, a vertical direction is a direction perpendicular to the main plane of extension of the substrate. According to at least one embodiment of the substrate, an arrangement of the structural elements has a plurality of

Accumulation areas. In particular, the

Clusters each at least two structural elements, for example, at least three structural elements. The

Surfaces of adjacent structural elements are

expediently at least in places from each other

spaced. In the accumulation areas, for example, the substrate has a higher surface occupation density

Structure elements as between adjacent

Accumulation areas. In other words, in the

Clustering areas a greater proportion of the surface of the deposition side formed by the structural elements than between adjacent clustering areas, for example, a minimum twice as large proportion. In contrast to a conventional substrate, the structural elements are therefore not equidistant in a uniform arrangement over the

Deposition side of the substrate distributed.

In at least one embodiment of the substrate, the substrate has a deposition side and a rear side opposite the deposition side, a plurality of structural elements being arranged on the deposition side and an arrangement of the structural elements having a plurality of Clustering areas each with at least three

Has structural elements.

In particular, the structural elements may be arranged such that an epitaxial growth on the substrate of

Gaps between the accumulation areas emanates.

Conveniently, a distance between adjacent

Structural elements within a cluster area so low that nucleation in the cluster areas

is negligible.

In accordance with at least one embodiment of the substrate, the accumulation areas are arranged in a regular grid, in particular in a regular hexagonal grid.

In particular, a cluster area overlaps with exactly one grid point of a regular grid. In doubt, one can determine the arrangement of the cluster areas

Centroid of the respective accumulation area

belonging to structural elements are determined. For example, the centroids are each arranged at a distance from a grid point of a regular grid, wherein the distance is at most 20%, preferably at most 10% of the distance between adjacent grid points. in the

Ideally, the centroids can also each lie exactly on a grid point of a regular grid, so that the distance is zero.

In accordance with at least one embodiment of the substrate, an arrangement of the structural elements is within one

Accumulation area equal to an arrangement of an adjacent accumulation area. For example, the arrangement of the

Structure elements within an accumulation area for

at least 50% of the accumulation areas or for all Clusters equal. The structural elements can thus be arranged in a periodically repeating pattern, with one period length being the center distance of the

Accumulation ranges corresponds.

As a center distance between two elements, a distance between the centers of the elements is considered in doubt. An external distance is in contrast the smallest

Distance between the outer borders of two elements.

In accordance with at least one embodiment of the substrate, there is a center distance between adjacent accumulation regions

at least twice, for example at least three times or at least four times as large as a center distance between adjacent structural elements of a cluster area.

In accordance with at least one embodiment of the substrate, a center distance of adjacent cluster regions is between 100 nm and 5 ym inclusive, for example between 400 nm and 4 ym inclusive.

In accordance with at least one embodiment of the substrate, a maximum lateral extent is an accumulation range of up to and including 0.2 times the center distance and including 0.99 times a center distance

neighboring accumulation areas. The larger the maximum

the lateral extent of an accumulation area in relation to the center distance of adjacent accumulation areas, the smaller the interspaces between adjacent accumulation areas

Be clustering areas.

According to at least one embodiment of the substrate, an outer distance between a cluster area and a Accumulation area nearest structural element

at least 50 nm. The outer distance gives the lateral

Extension of a free area between the accumulation area and the nearest structural element.

In particular, for each structural element at one edge of the accumulation area, an outer distance to the nearest

Structure element outside the accumulation area at least 50 nm. The structural elements closest to the accumulation area need not necessarily belong to the nearest accumulation area. Between

neighboring clustering areas can also have more

Structural elements can be arranged.

In accordance with at least one embodiment of the substrate, an inner spacing between two adjacent structural elements has an accumulation range of between 0 nm and 50 nm inclusive. The inner spacing gives the lateral extent of a free area between adjacent ones

Structure elements of an accumulation area. Two

adjacent structural elements can therefore in particular also adjoin one another directly. By a small

Inner spacing between adjacent structural elements can be avoided that in between spaces between these structural elements a significant growth in the

epitaxial deposition occurs.

In accordance with at least one embodiment of the substrate, at least one structural element of an accumulation region is at least one

associated adjacent structural element, which in a

Inner spacing of at most 50 nm is arranged to the structural element. In other words, it is

typically no structural element of a cluster area at a distance greater than 50 nm from a nearest cluster Structure element of the same accumulation area. Epitaxial growth within a cluster can be particularly effectively suppressed. According to at least one embodiment of the substrate, a vertical extent of at least a part of the

Structural elements, for example, of at least 50% of the structural elements or even all structural elements, between 100 nm inclusive and 1 ym, in particular between 200 nm inclusive and including 500 nm. It has been found that a vertical extent in this area favors efficient radiation extraction and at the same time, the layer thickness of the material to be deposited, which is required for complete lateral overgrowth, can be kept low, in particular in comparison to conventional structured substrates with structures in the micrometer range with typical heights of 1.4 .mu.m to 1.8 .mu.m. Stress-induced bending of the substrate can be reduced.

According to at least one embodiment of the substrate, at least some of the structural elements taper with increasing distance from the rear side of the substrate. For example, the structural elements taper along the entire circumference. A surface of the structural elements runs, for example, at least in places tilted to the back of the substrate. In particular, the surface of the runs

Structural elements tilts to an area between the

Accumulation areas. In the spaces between the

Structural elements, the separation side parallel to

Run back. Thus, by choosing appropriate

Separation parameters can be easily achieved by epitaxial growth of one on the substrate to be deposited material completely or at least

predominantly starting from gaps between the

Structural elements, in particular between the

Clustering occurs.

According to at least one embodiment of the substrate, at least a part of the structural elements has a basic shape of a cone, a truncated cone, a pyramid, a

Truncated pyramid, a cylinder or a prism. The pyramid, the truncated pyramid or the prism may have a particular regular polygonal base, for example, a base of a regular triangle or hexagon.

In accordance with at least one embodiment of the substrate, the structural elements contain sapphire. The structural elements can be formed, for example, by structuring the substrate body.

In accordance with at least one embodiment of the substrate, the structural elements contain an oxide material or a nitride material. For example, the structural elements are formed by structuring a layer arranged on the substrate body. Alternatively, the layer may also contain sapphire. In the spaces between the

Structural elements, the substrate body can be exposed.

A semiconductor device according to at least one

Embodiment a substrate with at least one of

above-mentioned features and arranged on the substrate, in particular epitaxially deposited

Semiconductor layer sequence on. For example, that is

Semiconductor device an optoelectronic Semiconductor device having an active area for generating and / or receiving radiation.

The substrate described above is for the

Semiconductor device particularly suitable. In connection with the substrate mentioned features can therefore be used for the semiconductor device.

Further embodiments and expediencies will become apparent from the following description of the embodiments in

Connection with the figures.

Show it:

Figures 1A, 1B and IC show a first embodiment of a substrate in plan view (Figure 1A) and in

Sectional view (Figure 1B) and such

Substrate having a semiconductor material deposited thereon (FIG. 1C); Figures 2A and 2B, a second embodiment of a

Substrate in sectional view (Figure 2A) and such a substrate with a deposited thereon semiconductor material (Figure 2B);

FIG. 3 shows a third exemplary embodiment of a substrate in FIG

Top view; and

FIG. 4 shows an exemplary embodiment of a semiconductor component in a sectional view.

The same, similar or equivalent elements are provided in the figures with the same reference numerals. The figures are each schematic representations and therefore not necessarily to scale. Rather, you can

comparatively small elements and in particular

Layer thicknesses for clarity to be shown exaggerated.

A first exemplary embodiment of a substrate 1 is shown schematically in plan view in FIG. 1A and in FIG. 1B in FIG

Section view shown.

The substrate 1 extends in a vertical direction, that is to say perpendicular to a main extension plane of the substrate, between a deposition side 10 and a rear side 11. A plurality of structural elements 2 are arranged on the deposition side 10. An arrangement of the structural elements has a plurality of accumulation areas 4. The clustering areas 4 each comprise a plurality of structural elements 2, in the exemplary embodiment shown seven structural elements by way of example. But it can also be a different number of

Structure elements apply, for example, two

Structural elements or more, especially three

Structural elements or more. During production, the structural elements 2 can be produced, for example, by means of a nanoimprint process.

The clustering areas 4 are each assigned a centroid 41. The centroids 41 are arranged on grid points of a regular hexagonal grid. One

Center distance 42 between adjacent cluster areas 4 is given by the spacing of adjacent centroids. The position of the centroids may, however, also differ from the position of the grid points. for example, no more than 20% of the distance between adjacent centroids.

An arrangement of the accumulation areas 4, which does not correspond to the arrangement in a regular grid, is conceivable as long as the arrangement of the structural elements

having mutually spaced accumulation areas.

The spacing of adjacent accumulation regions 4, in particular the center distance 42, is preferably between

including 100 nm and including 5 ym, preferably between 400 nm inclusive and 4 ym inclusive.

An outer distance 44 between a cluster area 4 and a cluster area closest to

Structural element 2 is large in comparison to the inner spacing 43 between adjacent structural elements within the

Accumulation area 4. The outer distance gives the lateral

Extension of an open area between a cluster area and a cluster area closest to the cluster area

Structure element. For example, the outer distance between an accumulation area and a structure element closest to the accumulation area is at least 50 nm. The inner spacing 43 of adjacent structural elements within the accumulation area 4 is preferably at most 50 nm. The smaller the inner spacing 43, the smaller the gaps 27 between adjacent structural elements be in the accumulation areas 4. In particular, the

Structural elements within the accumulation region 4 also locally adjacent to each other directly, so that the inner distance 43 is zero (see Figure 2A). For example, a maximum lateral extent of an accumulation area 4 is between 0.2 times and 0.99 times, respectively, a center distance of adjacent accumulation areas. The separation side 10 can be occupied comparatively large area with the structural elements 2, for example, with a total surface area of at least 60%.

In the exemplary embodiments shown, the

Structural elements 2 each have the same basic shape and the same size. However, there may be two or more than two

find different structural elements 2 application, which differ, for example, in terms of lateral extent, vertical extent and / or the basic geometric shape.

As illustrated in FIG. 1C, the growth in the epitaxial deposition of semiconductor material 5 proceeds from gaps 25 between the clustering regions 4 in a region 16 of the deposition side. The region 16 may in particular be contiguous via the separation side

extend. The cluster areas 4 become lateral

overgrow so that dislocations 50 with a

continue reduced dislocation density in the vertical direction in the semiconductor material. The crystal quality can be increased. In particular, the lateral extent of the clustering regions 4 can be large compared to the lateral ones

Extension of the structural elements 2 be. In other words, the lateral extent of the region to be epitaxially overgrown is not due to the lateral extent of the

Structural elements 2 themselves, but by the lateral

Extension of the accumulation areas 4 determined. In particular, the lateral extent of the epitaxial lateral to Overgrowing area, so the accumulation area 4, are also increased by increasing the number of structural elements within a cluster area. Compared to a conventional substrate with structures in the nanometer range, the dislocation density can be reduced and thus the

Crystal quality can be increased. At the same time, the total surface of the deposition side 10 increases, thereby increasing the likelihood of radiation deflection due to reflection and / or refraction, so that the

Outcoupling efficiency can be increased. In particular, the structural elements 2, which form a cluster area 4, can be significantly smaller in comparison to a conventional substrate with a microstructure, so that, for example, diffraction effects can occur for radiation in the visible, in particular in the blue and green spectral range or in the ultraviolet spectral range. As a result, a directional radiation and an overall increased coupling-out efficiency can be achieved. By the described arrangement of a plurality of structural elements 2 to accumulation regions 4 thus a high crystal quality and at the same time a high coupling-out efficiency can be achieved. In particular, the benefits of a conventional

Substrate with a microstructure and the advantages of a conventional substrate can be combined with a nanostructuring.

Furthermore, an efficient decoupling already with a comparatively small vertical extent of

Structural elements 2 can be achieved. For example, a vertical extent of some or all of the structural elements 2 is between 100 nm inclusive and 1 μm inclusive, in particular between 200 nm inclusive and including 500nm. Compared to conventional

Substrates with structures in the micrometer range, the thickness of the deposited material and thus the

stress-induced bending of the substrate 1 can be reduced.

The structural elements 2 are formed by structuring a substrate body 15, for example a sapphire substrate body. A surface 20 of the

Structural elements, in particular the entire surface 20, extends obliquely to the surface of the separation side 10 in FIG

Area 16 between the structural elements 2. By

Setting suitable growth parameters can be achieved that the nucleation probability in the epitaxial deposition in the region 16 is higher than at obliquely extending portions of the surface 20 of the structural elements.

The structural elements 2 may, for example, a basic shape of a cone or a pyramid with a polygonal

Have base area, such as a triangular, square or hexagonal basic shape. But there are also other forms in which the lateral extent of the structural elements tapers with increasing distance to the back 11, for example, a truncated pyramid or a

Truncated cone.

Furthermore, basic shapes with a constant cross section can also be used, for example the basic form of a

Cylinder or a prism. Structural elements 2 with such a basic shape are shown in FIG. 1A

suitably designed and arranged to each other that at least in places, the surfaces of adjacent Structural elements are spaced apart and spaces 25 between the structural elements arise.

In that shown in Figures 1A to IC

Embodiment, the structural elements 2 are arranged within a clustering region 4 to each other so that adjacent structural elements at any point directly adjacent to each other. However, the margins are so small that in the spaces 27 between adjacent

Structural elements 2 of a cluster area 4 no

significant epitaxial growth occurs and the

Clusters areas are covered by substantially epitaxially grown in the lateral direction semiconductor material. FIGS. 2A and 2B show an embodiment which substantially corresponds to the embodiment described in connection with FIGS. 1A to 1C. in the

In contrast to this, adjacent structural elements 2 within an accumulation area 4 adjoin one another directly. Depending on the basic shape of the structural elements 2, they can each form a closed area in a cluster area 4, for example in the case of a hexagonal area

Basic shape, as shown in Figure 3, in a triangular basic shape or in a square basic shape. Of the

For the sake of simplicity, only two accumulation areas 4 are shown in FIG. Thus, there are no gaps within the accumulation areas, so that an unwanted epitaxial growth can be completely excluded from such intervals. In this case, the

Structural elements 2 expediently with a

increasing distance from the back 11 tapering

Basic shape, so that the surfaces 20 of the Structural elements 2 at least in places from each other

are spaced.

Furthermore, in the second embodiment, the

Structure elements 2 formed by a layer 18 arranged on the substrate body 15. The layer contains

for example, an oxide material, such as silicon oxide or a nitride material, such as silicon nitride. The

Nucleation probability on such a layer is less than in the areas 16 in which the substrate body 15 is exposed. In the case of such a layer, therefore, structural elements having a basic shape in which the surface extends at least in places parallel to the region 16 are also suitable for the structural elements 2. In principle, all materials which are suitable for the layer 18 are suitable

Separation temperatures are temperature stable, for example at 1000 ° C.

Of course, such a layer 18 can also be used in the first embodiment. Accordingly, the structuring shown in Figure 2A can also in

Substrate body 15 are formed.

FIG. 4 shows a semiconductor component 8 with such a substrate 1. In this case, the semiconductor component 8 has, by way of example only, a substrate 1 which, as in FIG

Related to Figures 1A to IC described

is trained. Of course, a substrate according to one of the other embodiments may also be used.

On the substrate 1, a semiconductor layer sequence 81 is epitaxially deposited, for example by means of MOCVD. The Semiconductor device 8 is, for example, as a radiation-emitting semiconductor device, such as a

LED, formed. The semiconductor layer sequence 81 has an active region 85 provided for generating radiation. For external electrical contacting, the semiconductor device has contacts 86. The position and configuration of the contacts can be varied within wide limits, as long as charge carriers are injected from opposite sides into the active region 85 by the application of an external electrical voltage between the contacts 86 of the semiconductor component, where they emit emission

Radiation can recombine.

The semiconductor layer sequence 81, in particular the active region 85, is preferably based on a nitridic

Compound semiconductor material.

A peak wavelength of the radiation generated in the active region 85 may be in the material of the semiconductor layer sequence, for example between 0.2 times inclusive and including 5 times the center distance adjacent

Structure elements within a clustering range, so that a decoupling from the semiconductor device 8 can be particularly efficiently increased by the structural elements due to diffraction effects. In particular, the diffraction effects can promote directional radiation.

The invention is not limited by the description with reference to the embodiments. Rather, the includes

Invention every new feature as well as every combination of

Features, which includes in particular any combination of features in the claims, even if this feature or this combination itself is not explicitly in the Claims or the embodiments is given.

Reference sign list

1 substrate

10 separation side

11 back side

15 substrate body

16 area

18 shift

2 structural element

20 surface of the structural element

25 Space between accumulation points

27 Space between structural elements of a

accumulation point

4 accumulation area

41 centroid

42 Center distance of the accumulation areas

43 inner spacing of the structural elements in the

accumulation areas

44 External distance of the structural elements

5 semiconductor material

50 transfer

8 semiconductor device

81 semiconductor layer sequence

85 active area

86 contact

Claims

claims

1. substrate (1) having a separation side (10) and a deposition side opposite rear side (11), wherein on the separation side a plurality of structural elements (2) is arranged and an arrangement of the structural elements a plurality of accumulation areas (4), each with at least has two structural elements.

2. Substrate according to claim 1,

wherein the clustering areas are arranged in a regular grid.

3. Substrate according to claim 1 or 2,

wherein the clustering areas are arranged in a regular hexagonal grid.

4. Substrate according to one of the preceding claims,

wherein a pitch (42) between adjacent

Accumulation areas at least twice as large as one

Center distance between adjacent structure elements of a cluster area.

5. Substrate according to one of the preceding claims,

where a pitch of adjacent cluster areas

between 100 nm inclusive and 5 ym inclusive.

6. Substrate according to one of the preceding claims,

wherein a maximum lateral extent of a

Accumulation range between 0.2x including and 0.99x center distance

adjacent accumulation areas.

7. Substrate according to one of the preceding claims, wherein an outer distance (44) between an accumulation area and the accumulation area closest

Structural element is at least 50 nm.

8. Substrate according to one of the preceding claims,

wherein an inner spacing (43) between two adjacent structural elements of a cluster area between

including 0 nm and including 50 nm.

9. Substrate according to one of the preceding claims, wherein each structural element of a clustering region is associated with at least one adjacent structural element, which is arranged at an inner distance of at most 50 nm to the structural element.

10. Substrate according to one of the preceding claims,

wherein a vertical extension of at least a portion of the structural elements between and including 100 nm

including 1 ym.

11. Substrate according to one of the preceding claims,

wherein at least some of the structural elements with increasing distance from the back of the substrate

rejuvenate.

12. Substrate according to one of the preceding claims,

wherein at least a part of the structural elements has a basic shape of a cone, a truncated cone, a pyramid, a truncated pyramid, a cylinder or a prism.

13. Substrate according to one of the preceding claims, wherein the structural elements contain sapphire.

14. Substrate according to one of the preceding claims,

wherein the structural elements contain an oxide material or a nitride material.

15. Semiconductor component with a substrate according to one of the preceding claims and a semiconductor layer sequence arranged on the substrate.