Active solid-state devices (e.g. – transistors – solid-state diode – Incoherent light emitter structure – With heterojunction
Patent
1997-02-04
1998-06-02
Mintel, William
Active solid-state devices (e.g., transistors, solid-state diode
Incoherent light emitter structure
With heterojunction
257 96, 257 97, 257 99, 257103, 372 43, 372 44, 372 46, H01L 3300
Patent
active
057604223
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a light-emitting diode chip and a light-emitting diode using the same.
BACKGROUND ART
Conventionally, a GaAsP (gallium, arsenic and phosphorus)GaAs (gallium and arsenic)-type light-emitting diode chip and a GaP (gallium and phosphorus)-type light-emitting diode chip are well-known. Typically, the chips are made in a dice-like form having a rectangular surface (or square surface in particular) perpendicular to the laminating direction of material layers, and the length of each side of the rectangular surface is set at about 0.3-0.35 mm. For convenience of explanation, the size of a dice-shaped light-emitting diode chip will be represented hereinafter by the length of each side of the rectangular surface perpendicular to the laminating direction of the material layers.
Such a light-emitting diode chip as described above is used in a manner shown in FIG. 7 of the accompanying drawings. Specifically, the bottom surface of the light-emitting diode chip designated by reference sign (a) is formed with an overall electrode (b), whereas the top surface of the chip (a) is formed with a circular electrode pad (c). The overall electrode (b) of the chip (a) is bonded via conductive adhesive for example to a first electrode (e) formed on a suitable substrate (d). The electrode pad (c) is wire-bonded to a second electrode (f) formed on the substrate (d). Thus, current passage between the overall electrode (b) and the electrode pad (c) will drive an activated layer (g) formed in the chip (a) for light emission.
The light-emitting diode chip (a) shown in FIG. 7 is formed by a method in which a wafer including an n-clad layer, an activated layer, and a p-clad layer is prepared, and the wafer is divided by a dicing cutter into separate chips at the last step of the method. The electrode pad (c) is formed by etching away unnecessary portions of a gold layer which is formed beforehand over the top surface of the wafer by vacuum evaporation or sputtering. The electrode pad (c) is formed to have dimensions which enable proper ball-bonding of a gold wire the size of 20 .mu.m. Typically, the pad is made in the form of a circle of about 0.1 mm in diameter.
The chip size of a conventional light-emitting diode chip may be set at 0.3-0.35 mm for the purposes of that the dicing of a wafer is properly performed, that an optimum current density is obtained by a forward current of 10-20 mA which is conveniently provided by the power source of an ordinary electronic equipment, that the upper surface electrode pad does not unduly reduce the light-emitting area, and that the bonding is properly performed to the substrate by using a bonding collet.
However, the above-described conventional light-emitting diode chip or light-emitting diode using the same is not suitable as a light source for portable equipment, such as a portable telephone, which is expected to stand as long use as possible once a new battery is installed or the equipment is recharged. This is because the conventional light-emitting diode chip needs a forward current of 10-20 mA, thus requiring much power consumption and forcing the battery to discharge quickly only to make it difficult to keep the portable equipment in an operatable condition for a duration beyond a certain level.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide a light-emitting diode chip which provides sufficient luminosity by a smaller forward current.
Another object of the present invention is to provide a light-emitting diode using the above light-emitting diode chip.
Still another object of the present invention is to provide an advantageous method of using the above light-emitting diode chip.
According to a first aspect of the present invention, there is provided an InGaAlP-type light-emitting diode chip comprising a plurality of material layers in lamination, wherein the chip includes a rectangular surface perpendicular to a laminating direction of the material layers, and each side of the rectangular surface is no
REFERENCES:
patent: 5048035 (1991-09-01), Sugawara et al.
patent: 5153889 (1992-10-01), Sugawara et al.
patent: 5228044 (1993-07-01), Ohba
patent: 5404031 (1995-04-01), Sasaki et al.
patent: 5488233 (1996-01-01), Ishikawa et al.
patent: 5621225 (1997-04-01), Shieh et al.
Mintel William
Rohm & Co., Ltd.
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