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Semiconductor light-emitting device and method for manufacturing the same

Imported: 23 Feb '17 | Published: 22 Oct '02

Tien Yang Wang

USPTO - Utility Patents

Abstract

A semiconductor light emitting device comprising an AlGaInP lower confining layer, an AlGaInP active layer, an AlGaInP upper confining layer and a window layer on the upper confining layer using the MOVPE process. The device further contains a hybrid antireflection layer on the top surface and a lower conductive reflector at the substrate interface. The light emitting device has a high surface light-extraction efficiency due to reduced substrate absorption loss and light piping. The hybrid antireflective layer contains at least a conductor layer for uniform current injection and an oxide layer for light extraction and environmental stability.

The device structure contains a hybrid conductive transparent layer on the top surface and a conductive lower reflecting layer. Advantages of the LED in the present invention include highly efficient current-spreading and surface light extraction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be best understood by reference to the detailed description which follows, and to the accompanying drawings, in which:

FIG. 1 is a prior art transparent substrate LED with a window layer;

FIG. 2 is a prior art LED on GaAs substrate using a current-blocking layer and a DBR;

FIG. 3 is a prior art LED on GaAs substrate using a transparent conductive oxide layer with a current-blocking layer;

FIG. 4 is the calculated current spreading of GaP and ITO layers for a 250 um×250 um die and a contact pad diameter of 84 um;

FIG. 5 is the reflectance spectrum of a prior art DBR comprising a stack of 20 pairs of quarter wavelength GaAs/AlInP layers with a center reflectance at 570 nm;

FIG. 6 is the calculated angular variation of the reflectance of a GaAs/AlInP DBR;

FIG. 7 is a schematic diagram of an LED constructed in accordance with an illustrative embodiment of the present invention using a conductive antireflection stack;

FIG. 8 is the calculated transmittance, reflectance and absorbance spectrum of the hybrid antireflective stack of an LED constructed in accordance with an embodiment of the present invention comprising a 15 nm Ag layer and an upper 50 nm tin oxide layer;

FIG. 9 is the calculated angular variation of the transmittance, reflectance and absorbance at 600 nm of the hybrid antireflective stack of an embodiment of an LED constructed in accordance with the present invention comprising 15 nm Ag and 50 nm tin oxide layer;

FIG. 10 is a schematic diagram of an LED constructed in accordance with an embodiment of the present invention containing a hybrid reflective layer at the substrate interface;

FIG. 11 is the calculated reflectance spectrum of the hybrid reflective layer of an LED constructed in accordance with an embodiment of the present invention comprising 50 nm Ag and 50 nm indium tin oxide layer;

FIG. 12 is the calculated angular variation of the reflectance at 600 nm of the hybrid reflective layer of the LED in the present invention comprising 50 nm Ag and 50 nm indium tin oxide layer;

FIG. 13 is a schematic diagram of an LED in accordance with the present invention using a hybrid conductive antireflection stack on a textured surface; and

FIG. 14 is a schematic diagram of an LED in accordance with an embodiment of the present invention using a textured surface antireflection layer and a lower reflective layer.

Claims

1. A semiconductor light-emitting device comprising:

2. The device of claim 1, wherein said second metal layer comprises silver having a thickness of from 30 to 150 nm.

3. The device of claim 1, wherein said second transparent conductive oxide layer comprises indium tin oxide having a thickness of from 20 to 100 nm.