WO2002043160A1

WO2002043160A1 - Light emitting semiconductor components and method for production thereof

Info

Publication number: WO2002043160A1
Application number: PCT/DE2001/004396
Authority: WO
Inventors: Robert Averbeck; Henning Riechert
Original assignee: Infineon Technologies Ag
Priority date: 2000-11-24
Filing date: 2001-11-22
Publication date: 2002-05-30

Abstract

A germanium- and/or carbon-containing silicon-alloy is applied to a substrate made, in particular, from silicon, in or on which a light-active material, for example, III-V semiconductor material, in particular, indium arsenide, is applied.

Description

description

LIGHT-EMITTING SENSOR COMPONENTS AND METHOD FOR THE PRODUCTION THEREOF

The invention relates to semiconductor components and methods for producing a semiconductor component.

Such a semiconductor component and such a method for its production are known from [1].

In the semiconductor component known from [1], indium arsenide quantum dots (InAs quantum dots) are embedded in a silicon matrix.

In the case of such a semiconductor component, it has been found that, owing to the quantum dots formed in the indium arsenide as the semiconductor material, photons, that is to say light rays, are generated in principle.

However, with the structure known from [1], that is to say with this semiconductor component, it has been found that this semiconductor component is not suitable for generating light with sufficient efficiency. The reason for this is stated in [1] that the optical transitions of the electrons or their recombination with holes are indirect both in the impulse space and in the space.

So there are no hetero structures in one

Material system with silicon and / or silicon germanium, which allow the generation of light beams with a sufficiently high degree of efficiency that even approximately corresponds to the efficiency of semiconductor components in materials with a direct energy band gap, for example II-VI semiconductors or III-V semiconductors , From [2] it is also known to introduce an alloy of indium-gallium-arsenide-antimonide in the form of quantum dots into a silicon layer and to locate it there.

An optical semiconductor device is described [3], which has a layer structure with Si layers, SIC layers and SiGeC layers arranged one on top of the other. According to [3], the optical semiconductor device has a material with an indirect band gap as the material for the optically active layer.

[4] describes a laser diode which, as an optically active layer, has a quantum well layer made of a material with an indirect band gap.

[5] also describes a method for producing an optoelectronic device which has steps of a low-temperature deposition process and a corresponding temperature treatment of the device.

An overview of organometallic CVD in GalnAsSb alloys can be found in [6].

Furthermore, an HgCdTe laser is described in [7], which is formed using an MBE method.

Fundamentals about mechanical stresses in quantum wires, quantum dots and in silicon substrates are given in [8].

The invention is therefore based on the problem of specifying a semiconductor component based on a material system with silicon and / or silicon germanium and / or silicon germanium carbon, in which light is generated with an efficiency which is improved compared to the semiconductor component known from [1]. The problem is solved by the semiconductor component and by the method for producing a semiconductor component with the features according to the independent patent claims.

A semiconductor component has a substrate, for example made of silicon, preferably n-doped silicon or p-doped silicon.

Alternatively, the substrate may also contain Siι_ _yGe _x _x Cy with 0 <x <1 and 0 <y <1 and x + y <. 1

If the substrate has a silicon-germanium-carbon alloy, then the stresses, that is to say the mechanical stresses within the entire semiconductor component, can be specified, that is to say adjusted, by means of this material, in which an alloy selected in accordance with the desired stress to be set with the corresponding Shares of germanium and carbon are used within the silicon alloy.

A first layer with Siι_ _x _yGe _x Cy with 0 <x <1 and 0 <y <1 and x + y <1 is applied to the substrate. In turn, a light-active layer made of a material with a direct band gap, for example a III-V semiconductor material or a II-IV semiconductor material, is applied to the first layer. Furthermore, a second layer with Siι_ _s _ Ge _s Ct with 0 <s <1 and 0 <t <1 and s + t <1 is applied to the light-active layer.

The photoactive layer may according to an embodiment of the invention from a material with a direct energy band gap of the general matrix-inaGai aASfoSbi- _b 0 ≤ a ≤ 1 and contain 0 <b <. 1 The light-active layer can in particular be indium arsenide (InAs). The light-active layer, that is, the actually active material for

Light generation, that is, for generating light rays is a very thin layer, the thickness of which is in a range of one a so-called quantum well layer up to approximately 5 nm thick is provided.

Alternatively, this layer can also be grown in the form of self-grown indium gallium arsenide

Antimonide quantum dots are present, which are introduced into the first layer, which according to this embodiment is the same as the second layer, that is to say x = s and y = t as quantum dots in the silicon material which preferably contains germanium and / or carbon.

In this way, it is possible for the first time to enclose electrical charge carriers, that is to say electrons and holes, in a silicon-based material system, that is to say a semiconductor component, in a central region, the light-active layer, which is made of III-V semiconductor material or II-VI Semiconductor material exists.

Alternatively, the material with a direct band gap can contain a II-IV semi-material, for example Hg _< 3Cdι_ciTe _e Seι_ _e with 0 <d <1 and 0 <e <1.

According to a preferred embodiment of the invention, it is provided that the first layer and / or the second layer or the layer applied to the substrate, into which light-active material with a direct band gap is introduced, Siι_ _x _ _y Ge _x Cy with 0 <x < Contains 0.5 and 0 <y <0.1.

A cover layer for protecting the semiconductor component can be applied on the second layer or on the layer applied to the substrate.

The invention can clearly be seen in the fact that the use of a silicon-germanium-carbon alloy as a layer, into which light-active material is introduced, or between two such layers, a layer with light-active material is introduced is to set both the energy band gap and the band edge jumps to the light-active material in the energy band independently of one another, as a result of which the overall efficiency, that is to say the efficiency of the semiconductor component with regard to the generation of light beams, is considerably increased.

The band edge jumps between the light-active material, for example indium arsenide and the layer of the alloy of silicon-germanium-carbon that surrounds the light-active material, can be dimensioned such that both electrons and holes are localized in the light-active material and thereby the probability of recombination and the resulting generation of light rays is significantly increased.

For this reason, the semiconductor component is particularly suitable as a semiconductor laser or as a light-emitting diode.

The thickness of the semiconductor device should according to one

Embodiment of the invention may be less than a critical thickness at which dislocations are formed within the semiconductor device.

The compositions and the tensions of the materials are preferably to be set such that the band gap is narrowed in each case and the band edges are cracked in such a way that the electrical charge carriers, that is to say the electrons and the holes, into or out of the active layer made of III-V semiconductors II-VI semiconductors migrate and are localized there.

In a method for producing a semiconductor component, a first layer with Siι_ _x _yGe _x Cy with 0 x x 1 1 and 0 <y <1 and x + y <1 is applied to a substrate. In a further step, a light-active layer made of a material with direct energetic band gap applied and a second layer with Siι-_ _s _tGe _s Ct with 0 <s <1 and 0 <t <1 and s + t <1 is applied to the light-active layer.

In an alternative method, a layer with Siι-- _x _yGe _x Cy with 0 <x <1 and 0 <y <1 and x + y <1 is applied to a substrate. In a subsequent step, light-active material with a direct band gap is introduced into this layer.

According to an embodiment of the invention, a method of molecular beam epitaxy (molecular beam epitaxy method, MBE method) can be carried out to apply the layers.

As an alternative or in addition, a deposition process from the gas phase (CVD process) can be used to apply the layers, in particular to apply the first and / or the second layer.

An embodiment of the invention is shown in the figures and is explained in more detail below.

Show it

Figures la to Id the structure of a semiconductor laser (or a light emitting diode) according to a first embodiment of the invention (Figure la) and cross sections of layer structures during the manufacturing process of the semiconductor device

(Figures lb to ld);

Figures 2a to 2d a semiconductor device according to a second embodiment of the invention (Figure 2a) and cross sections of layer structures during the

Manufacturing method of the semiconductor device (Figures 2b to 2d). Fig.la shows a semiconductor laser (or a light emitting diode) 100 according to a first embodiment of the invention.

On an n-doped silicon substrate 101 of basically any thickness, in accordance with this exemplary embodiment having a thickness of 1000 μm, there is a first layer 102 made of silicon-germanium-carbon of the alloy Siι_ _yGe _x Cy with 0 <x <0.5 and 0 <y <0.1 applied by means of a suitable CVD method.

The first layer 102 has a thickness of approximately 100 nm to 2 μm (cf. FIG. 1b).

On the first layer 102, a layer of light-active material according to this exemplary embodiment is a layer of

Indium renside 103 applied in a thickness of 0 to 20 nm, it being noted that the dimensioning of the individual layer thicknesses is not critical.

An MBE method is used to apply the light-active layer 103 (cf. FIG. 1c).

As shown in FIG. 1d, a second layer 104 made of a silicon-germanium-carbon alloy is deposited on the light-active layer 103 in the same way as the first layer 102 by means of a suitable CVD method.

The second layer 104 contains the same material as the second layer 102.

In other words, the second layer 104 is made of the same material as the first layer 102.

According to this first exemplary embodiment, the thickness of the second layer 104 is likewise 100 nm to 2 μ. As shown in Fig.la, a cover layer 105 made of p-doped silicon is applied to the second layer 104. The cover layer, which is used in particular for the electrical contact of the semiconductor component, has a fundamentally uncritical thickness according to this exemplary embodiment of 100 nm to 2 μm.

In this connection, it should be noted that the total layer thickness, starting from the lower surface of the first layer 102 to the upper surface of the cover layer 105, should not be greater than a critical layer thickness, that is to say as a layer thickness, during the dislocations within the individual layers be formed.

Damage to the semiconductor component 100 is avoided in this way.

2a to 2D show a semiconductor laser according to a second exemplary embodiment of the invention.

As shown in FIGS. 2a and 2b, an n-doped silicon layer is likewise provided as substrate 201 with a thickness of 500 μm in accordance with this exemplary embodiment.

On the substrate 201 is a layer of an alloy of silicon germanium carbon, according to this

Embodiment Siι_ _x _yGe _x Cy with 0 <x <0.5 and 0 <y ≤ 0.1 applied by means of a suitable CVD method. The layer 202 has a thickness of 100 nm to 2 μm.

As shown in FIG. C, by means of a method known from [2], light-active material, according to the second exemplary embodiment, any alloy of indium-gallium-arsenide-antimonide, that is, InaGai-aAs ^ Sb ^ with 0 <a <1 and 0 <b <1 in the form of quatendots 203 in the Layer 202 introduced and localized there, which is symbolized in FIG. 2c by arrows 205.

FIG. 2D shows the state in which the quantum dots 203 made of the light-active material are introduced into the layer 202 and are therefore localized.

A silicon cover layer 204 with a thickness of 10 μ is grown on the layer 202 by means of an MBE method.

The following publications are cited in this document:

[1] R.Heitz et al, Optical properties of InAs quantum dots in a Si matrix, Applied Physics Letters, Volume 74, No. 12, pp. 1701-1703, March 1999

[2] A. Egorov et al, Self-organized InAs Quantum Dots in a Silicon matrix, Journal of Crystal Growth, Vol. 201/202, pp. 1202-1204, 1999

[3] US 5,523,592

[4] US 6,151,347

[5] US 6,124,147

[6] Shuwei Li et al, Growth of GalnAsSb alloys by metalorganic chemical vapor deposition, Journal of Crystal Growth, 156, pp. 39-44, 1995

[7] M. Zandian et al, HgCdTe double heterostructure injection laser grown by molecular beam epitaxy, Applied Physics Letter, Vol. 59, No. 9, pp. 1022-1024, August 1991

[8] SC Jain, Stresses and strains in lattice-mismatched stripes, quantum wires, quantum dots, and Substrates in Si technology, Journal of Applied Physics, Vol. 79, No. 11, pp. 8145-8165, June 1996 LIST OF REFERENCE NUMBERS

100 semiconductor lasers

101 substrate

102 First shift

103 Light-active layer

104 Second shift

105 top layer

200 semiconductor lasers

201 substrate

202 silicon-germanium-carbon 203 light-active material 204 top layer 205 arrow

Claims

claims

1. Semiconductor device with

• a substrate, • a first layer applied to the substrate with Siι_ _x --yGe _x Cy with 0 <x <1 and 0 y <1 and x + y <1, ® a light-active applied on the first layer

Layer of a material with a direct band gap, and β of a second layer applied to the light-active layer with Siι_ _s --tGe _s C _t with 0 <s <1 and 0 <t <1 and s + t <1.

2. Semiconductor component with ® a substrate, ® at least one layer applied to the substrate with Siι_ _x _yGe _x C _y with 0 <x <1 and 0 y <1 and x + y <1,

• Light-active material with a direct band gap introduced into the layer.

3. The semiconductor component as claimed in claim 2, in which the light-active material is introduced into the layer as quantum dots.

4. Semiconductor component according to one of claims 1 to 3, in which the substrate contains Si or Siι_ _yGe _x Cy with 0 <x <1 and 0 <y <1 and x + y <1.

5. Semiconductor component according to one of claims 1 to 4, wherein the material with a direct band gap is a III-V

Is semiconductor material.

6. The semiconductor device according to claim 5, wherein the material with a direct band gap In _a Gaι-- _a AΞ] _D Sbι--] _D with 0 <a <1 and 0 <b <1.

7. A semiconductor device according to any one of claims 1 to 4, wherein the material with a direct band gap is a II-VI semiconductor material.

8. The semiconductor device according to claim 7, wherein the material with a direct band gap Hg ^ (Cd _e Teι_ _e ) _ _< with 0 <d <1 and 0 <e <1.

9. The semiconductor component according to one of claims 1 to 8, wherein the first layer and the second layer contain the same material.

10. Semiconductor component according to one of claims 1 to 9, in which the first layer and / or the second layer or the layer applied to the substrate Siι_ _x _yGe _x Cy with 0 <x <0, 5 and 0 <y <0.1 contains.

11. Semiconductor component according to one of claims 1 to 10, with a cover layer applied to the second layer or to the layer applied to the substrate.

12. The semiconductor component according to claim 11, wherein the cover layer Si or Siι_ _x _yGe _x Cy with 0 <x <1 and 0 <y <1 and x + y <1 contains.

13. The semiconductor component according to one of claims 1 to 12, wherein the thickness of the semiconductor component is less than a critical thickness at which dislocations are formed within the semiconductor component.

14. The semiconductor component according to one of claims 1 to 13, in which the semiconductor component is a semiconductor laser or a light-emitting diode.

15. A method for producing a semiconductor component, In which a first layer with Siι_ _x _yGe _x Cy with 0 <x <1 and 0 <y <1 and x + y <1 is applied to a substrate,

• in which a light-active layer made of a material with a direct band gap is applied to the first layer, and

• in which a second layer with Siι_ _s _ Ge _s Ct with 0 <s <1 and 0 <t <1 and s + t <1 is applied to the light-active layer.

16. A method for producing a semiconductor component,

® in which a layer with Siι_ _x _yGe _x Cy with 0 <x <1 and 0 <y <1 and x + y <1 is applied to a substrate, and • in which light-active material with a direct band gap is introduced into the layer.

17. The method according to claim 15 or 16, in which at least partially a method of molecular beam epitaxy is carried out for applying the layers.

18. The method according to any one of claims 15 to 17, in which a deposition process from the gas phase is carried out at least partially to apply the layers.

19. The method according to claim 18, wherein the deposition process from the gas phase is used to apply the first layer and / or the second layer.