Semiconductor chip for optoelectronics

• US 7,145,181 B2
• Filed: 04/26/2002
• Issued: 12/05/2006
• Est. Priority Date: 04/27/2001
• Status: Expired due to Term

• Current Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Original Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Inventors: Wirth, Ralph
• Primary Examiner(s): RICHARDS, NORMAN DREW
• Application Number:
  US10/476,121
• Publication Number:
  US 20040195641A1
• Time in Patent Office: 1,684 Days
• Field of Search: 257/95, 257/98, 257/99, 257/100, 257/E33.067, 257/E33.068, 257/E33.07, 257/E33.074
• US Class Current: 257/95
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/38 with a particular shape

Abstract

A semiconductor chip, in particular a light-emitting diode, has a substrate (2), on which a sequence of semiconductor layers (3) with an active zone (5) has been applied. Above the sequence of semiconductor layers (3) there is a stepped window layer (6), which is structured in the manner of a Fresnel lens and has with regard to the coupling out of radiation the function of a hemispherical lens (7). This produces a semiconductor chip with particularly high coupling-out efficiency.

Claims

1. A semiconductor chip for optoelectronics comprising:

a substrate (2);

a sequence of semiconductor layers (3) arranged on and above said substrate and including a photon-emitting active zone (5);

a window layer (6) directly applied to and above said sequence of semiconductor layers;

wherein a region of said window layer (6) has a Fresnel lens type of stepped structure arranged so that in said region of the window layer radiation emitted from the active zone (5) impinges on said stepped structure; and

wherein the semiconductor chip has a central contact point arranged above the active zone (5) on a surface of said window layer not in contact with the sequence of semiconductor layers.

2. The semiconductor chip as claimed in claim 1, wherein steps in said stepped structure in the region of the window layer are respectively portioned projections of surface regions of an imaginary lens (7) in the form of a hemisphere in the direction of its center point, centered on the active zone (5).

3. The semiconductor chip as claimed in claim 2, wherein the following applies for the diameter d_A of the active zone:

d_A<

d_H×

n_M/n_H

where d_H is the diameter of the imaginary hemisphere (7), n_H is the refractive index of the window layer (6) and n_M is the refractive index of the medium in contact with the window layer (6).

4. The semiconductor chip as claimed in claim 2, wherein the structured region of the window layer (6) is approximated in cross section to a polygon.

5. The semiconductor chip as claimed in claim 1, wherein the semiconductor chip has a contact point (9) outside the window layer (6).

6. The semiconductor chip as claimed in claim 1, wherein the central contact point (9) is arranged on a surface of the window layer facing away from the substrate.

7. The semiconductor chip as claimed in claim 1, wherein the window layer is electrically conductive.

8. A semiconductor chip for optoelectronics comprising:

a substrate (2);

a sequence of semiconductor layers (3) arranged on and above said substrate and including a photon-emitting active zone (5);

a window layer (6) directly applied to and above said sequence of semiconductor layers;

wherein a region of said window layer (6) has a Fresnel lens type of stepped structure arranged so that in said region of the window layer radiation emitted from the active zone (5) impinges on said stepped structure;

wherein the semiconductor chip has a central contact point arranged above the active zone (5) and a contact point (9) outside the window layer (6); and

wherein from the contact point (9) a contact bridge (11) leads to the active zone.

9. A semiconductor chip for optoelectronics comprising:

a substrate (2);

a sequence of semiconductor layers (3) arranged on and above said substrate and including a photon-emitting active zone (5);

a window layer (6) directly applied to and above said sequence of semiconductor layers;

wherein a region of said window layer (6) has a Fresnel lens type of stepped structure arranged so that in said region of the window layer radiation emitted from the active zone (5) impinges on said stepped structure;

wherein the semiconductor chip has a central contact point arranged above the active zone (5); and

wherein a reflective layer is arranged between the active zone (5) and the substrate (2).

10. A semiconductor chip for optoelectronics comprising:

a substrate (2);

a sequence of semiconductor layers (3) arranged on and above and above said substrate and including a photon-emitting active zone (5);

a window layer (6) directly applied to and above said sequence of semiconductor layers;

wherein a region of said window layer (6) has a Fresnel lens type of stepped structure arranged so that in said region of the window layer radiation emitted from the active zone (5) impinges on said stepped structure;

wherein the semiconductor chip has a central contact point arranged above the active zone (5); and

wherein a contact bridge is arranged on the surface of the window layer facing away from the substrate.

11. A semiconductor chip for optoelectronics comprising:

a substrate (2);

a sequence of semiconductor layers (3) arranged on said substrate and including a photon-emitting active zone (5);

a window layer (6) directly applied to said sequence of semiconductor layers;

wherein a region of said window layer (6) has a Fresnel lens type of stepped structure arranged so that in said region of the window layer radiation emitted from the active zone (5) impinges on said stepped structure;

wherein the semiconductor chip has a contact point (9) outside the window layer (6); and

wherein from the contact point (9) a contact bridge (11) leads to the active zone.

12. A semiconductor chip for optoelectronics comprising:

a substrate (2);

a sequence of semiconductor layers (3) arranged on said substrate and including a photon-emitting active zone (5);

a window layer (6) directly applied to said sequence of semiconductor layers;

wherein a region of said window layer (6) has a Fresnel lens type of stepped structure arranged so that in said region of the window layer radiation emitted from the active zone (5) impinges on said stepped structure; and

wherein a contact bridge is arranged on the surface of the window layer facing away from the substrate.