Semiconductor layer structure with superlattice

• US 8,022,392 B2
• Filed: 07/20/2007
• Issued: 09/20/2011
• Est. Priority Date: 07/27/2006
• Status: Active Grant

• Current Assignee: OSRAM OLED GMBH (Ams-Osram AG)
• Original Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Inventors: Miler, Andreas, Eichler, Christoph, Lell, Alfred, Schillgalies, Marc
• Primary Examiner(s): Vu; Hung
• Assistant Examiner(s): Webb; Vernon P
• Application Number:
  US11/780,516
• Publication Number:
  US 20080054252A1
• Time in Patent Office: 1,523 Days
• Field of Search: 257/22, 257/E29.005, 257/E29.078, 257/E33.008, 257/103
• US Class Current: 257/22
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 29/155 Comprising only semiconductor materials H01L29/154 takes precedence
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/04 with a quantum effect structure or superlattice, e.g. tunnel junction
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01S 5/2009 by using electron barrier layers
• CPC Class Codes: H01S 5/3215 graded composition cladding layers
• CPC Class Codes: H01S 5/3216 quantum well or superlattice cladding layers
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

The semiconductor layer structure includes an active layer and a superlattice composed of stacked layers of III-V compound semiconductors of a first and at least one second type. Adjacent layers of different types in the superlattice differ in composition with respect to at least one element. The layers have predefined layer thicknesses, such that the layer thicknesses of layers of the first type and of the layers of the second type increase from layer to layer with increasing distance from an active layer. An increasing layer thickness within the layers of the first and the second type is suitable for adapting the electrical, optical and epitaxial properties of the superlattice to given requirements in the best possible manner.

Claims

1. A semiconductor layer structure comprising an active layer and a superlattice composed of stacked layers of a first type and at least one second type, wherein

said layers of said first type and of said at least one second type are III-V compound semiconductors,

adjacent layers of different types in said superlattice differ in composition with respect to at least one element,

said layers have predefined layer thicknesses, and

layer thicknesses of said layers of said first type and said layers of said second type increase from layer to layer with increasing distance from said active layer.

2. The semiconductor layer structure as in claim 1, wherein said superlattice comprises alternately stacked In_xAl_yGa_1-x-yN and In_wAl_zGa_1-w-zN layers where 0≦

x,y,w,z≦

1 and x+y≦

1 and w+z≦

1.

3. The semiconductor layer structure as in claim 1, wherein said superlattice comprises alternately stacked In_xAl_yGa_1-x-yP and In_wAl_zGa_1-w-zP layers where 0≦

x,y,w,z≦

1 or alternately stacked In_xAl_yGa_1-x-yAs and In_wAl_zGa_1-w-zAs layers where 0≦

x,y,w,z≦

1 and x+y≦

1 and w+z≦

1.

4. The semiconductor layer structure as in claim 1, wherein the individual said layers of said superlattice are each assigned a vertical position within said semiconductor layer structure, and the layer thickness of a said layer is dependent on the vertical position of that layer within said semiconductor layer structure.

5. The semiconductor layer structure as in claim 4, wherein said dependence of the layer thickness of a said layer on said vertical position is defined by a common function for all said layers of said superlattice.

6. The semiconductor layer structure as in claim 4, wherein said dependence of the layer thickness of a said layer on said vertical position is defined by a first function for layers of said first type and by at least one second function for layers of said at least one second type.

7. The semiconductor layer structure as in claim 5, wherein said first and/or said at least one second and/or said common function is a step function or a monotonously rising/falling function or a linear function or a polynomial function or an exponential function or a logarithmic function or a periodic function or a superposition of the aforesaid functions or contains fractions of one of said functions.

8. The semiconductor layer structure as in claim 1, wherein at least the said layers of a same type in said superlattice differ in composition.

9. The semiconductor layer structure as in claim 1, wherein the content of a material component in at least the said layers of a same type increases from layer to layer with increasing distance from said active layer.

10. An optoelectronic component comprising a semiconductor layer structure as in claim 1.

11. The optoelectronic component as in claim 10, which is a light-emitting diode.

12. The optoelectronic component as in claim 10, which is a laser diode.