Active solid-state devices (e.g. – transistors – solid-state diode – Incoherent light emitter structure – With reflector – opaque mask – or optical element integral...
Reexamination Certificate
2003-06-24
2004-08-24
Ngô, Ngân V. (Department: 2814)
Active solid-state devices (e.g., transistors, solid-state diode
Incoherent light emitter structure
With reflector, opaque mask, or optical element integral...
C257S103000, C438S029000, C438S042000
Reexamination Certificate
active
06781160
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a semiconductor light emitting device and a method for manufacturing the same, and more particularly, to a semiconductor light emitting device having a light scattering-deflecting layer and a method for manufacturing the same.
BACKGROUND OF THE INVENTION
Semiconductor light emitting devices, such as light emitting diodes (LED), are formed by using semiconductor materials. The semiconductor light emitting devices are one kind of minute solid-state light sources that can transform electrical energy into light energy. The semiconductor light emitting devices not only have the features of small volume, long life, low driving voltage, rapid response speed, and shockproof, but also can meet the needs of various application apparatuses of lightness, thinness, and miniaturization, thus having become very popular electric products in daily life.
Referring to
FIG. 1
,
FIG. 1
illustrates a cross-sectional view of a conventional semiconductor light emitting device. In the formation of the semiconductor light emitting device, a semiconductor layer
102
is first formed on a substrate
100
that is transparent by using a deposition method, and a n-type semiconductor layer
104
is formed on the semiconductor layer
102
by using an epitaxy method. Then, a luminescent structure
106
is formed on the n-type semiconductor layer
104
by using an epitaxy method similarly. A p-type semiconductor layer
108
is formed on the luminescent structure
106
similarly by using an epitaxy method, wherein the n-type semiconductor layer
104
, the luminescent structure
106
, and the p-type semiconductor layer
108
constitute a semiconductor light emitting structure.
Next, a definition step is performed by using a photolithograph technique and an etching technique to remove a portion of the luminescent structure
106
and a portion of the p-type semiconductor layer
108
, so as to expose a portion of the n-type semiconductor layer
104
. Thereafter, an electrode
110
and an electrode
112
are formed respectively on the p-type semiconductor layer
108
and on the n-type semiconductor layer
104
by using a thermal evaporation method, an e-beam evaporation method, or an ion sputtering method, so as to complete the semiconductor light emitting device.
SUMMARY OF THE INVENTION
An objective of the present invention is to provide a semiconductor light emitting device, such as a light emitting diode, the semiconductor light emitting device comprising a semiconductor layer having a scraggly surface and a light scattering-deflecting layer of which a refractive index is different from that of the semiconductor layer. Therefore, light is deflected while the light enters the semiconductor layer from the light scattering-deflecting layer, and the light is scattered while the light enters the scraggly surface of the semiconductor layer, so that the semiconductor light emitting device emits more light.
Another objective of the present invention is to provide a method for manufacturing a semiconductor light emitting device, by forming a semiconductor layer having a scraggly surface, and then forming a light scattering-deflecting layer of which a refractive index is different from that of the semiconductor layer. Thus, after light is deflected by the light scattering-deflecting layer and scattered by the semiconductor layer, the light emitting efficiency of the semiconductor light emitting device can be enhanced.
According to the aforementioned objectives of the present invention, the present invention provides a semiconductor light emitting device comprising: a transparent substrate, wherein the transparent substrate comprises a semiconductor layer formed thereon, and the semiconductor layer comprises a scraggly surface; a light scattering-deflecting layer located on the scraggly surface of the semiconductor layer; and a semiconductor luminescent epitaxial structure located on the light scattering-deflecting layer. A refractive index of the light scattering-deflecting layer is different from that of the semiconductor layer.
According to a preferred embodiment of the present invention, the light scattering-deflecting layer can fill up and level the scraggly surface of the semiconductor layer, or can be conformal with the scraggly surface of the semiconductor layer.
According to the aforementioned objectives of the present invention, the present invention provides a method for manufacturing a semiconductor light emitting device comprising the following steps: providing a transparent substrate, wherein the transparent substrate comprises a semiconductor layer formed thereon, and the semiconductor layer comprises a scraggly surface; forming a light scattering-deflecting layer located on the scraggly surface of the semiconductor layer; and forming a semiconductor luminescent epitaxial structure located on the light scattering-deflecting layer.
According to a preferred embodiment of the present invention, the step of forming the light scattering-deflecting layer is performed by using a metal organic chemical vapor deposition (MOCVD) method to fill up and level the scraggly surface of the semiconductor layer.
The refractive index of the light scattering-deflecting layer is different from that of the semiconductor layer, and the semiconductor layer has a scraggly surface, so that light is deflected and scattered while the light enters the semiconductor layer from the light scattering-deflecting layer. Therefore, the semiconductor light emitting device can emit more light, thus achieving the objective of enhancing the light emitting efficiency.
REFERENCES:
patent: 5818066 (1998-10-01), Duboz
patent: 6252253 (2001-06-01), Bao et al.
patent: 6316785 (2001-11-01), Nunoue et al.
patent: 6630684 (2003-10-01), Lee et al.
Chang Chih-Sung
Chen Tzer-Perng
Tsai Tzong-Liang
Glenn Michael A.
Glenn Patent Group
Ngo Ngan V.
United Epitaxy Company Ltd.
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