Semiconductor device manufacturing: process – Making device or circuit emissive of nonelectrical signal – Packaging or treatment of packaged semiconductor
Reexamination Certificate
2001-05-23
2004-02-10
Chaudhuri, Olik (Department: 2823)
Semiconductor device manufacturing: process
Making device or circuit emissive of nonelectrical signal
Packaging or treatment of packaged semiconductor
C438S035000, C438S046000
Reexamination Certificate
active
06689630
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to luminescent emitter layers, luminescent devices, and methods of fabricating the same. Electroluminescent, cathodoluminescent, and photo luminescent emitter layers may be used in a variety of display technology applications. Indeed, a significant amount of research has been devoted to developing thin film luminescent emitter layers. A variety of preferred compositions have been developed. However, despite these technological advances, there is a continuing drive to develop high performing, efficient, inexpensive, and readily producible luminescent emitter layers.
BRIEF SUMMARY OF THE INVENTION
This need is met by the present invention wherein a variety of optimal luminescent emitter layers, luminescent devices, and methods of fabricating the same are provided. In accordance with one embodiment of the present invention, an alternating current thin film electroluminescent device is provided comprising an AC power source and an emitter layer positioned between a pair of electrode layers. One of the pair of electrode layers is transparent to visible light of a selected wavelength. The AC power source is connected across the pair of electrode layers. The emitter layer comprises a non-conductive amorphous alloy comprising aluminum nitride and an Er luminescent center. The emitter layer and the pair of electrode layers are arranged such that, upon activation of the AC power source, an electric field is created between the electrode layers across the emitter layer. The aluminum nitride and the Er luminescent center are provided in proportions selected such that the electric field causes emission of visible light of the selected wavelength from the emitter layer.
In accordance with another embodiment of the present invention, a method of fabricating an alternating current thin film electroluminescent device is provided. According to the method, a non-conductive amorphous film comprising aluminum nitride and an Er luminescent center is prepared by RF magnetron sputtering an Al target and an Er target in a nitrogenous atmosphere, at room temperature, under vacuum. The amorphous film is activated to form an emitter layer by annealing at or above about 1023 K. The emitter layer is positioned between the pair of electrode layers. An AC power source is connected across the pair of electrode layers. The emitter layer and the pair of electrode layers are arranged such that, upon activation of the AC power source, an electric field is created between the electrode layers across the emitter layer. The aluminum nitride and the Er luminescent center are provided in proportions selected such that the electric field causes emission of visible light of the selected wavelength from the emitter layer.
In accordance with yet another embodiment of the present invention, a method of fabricating an amorphous luminescent emitter layer comprising aluminum nitride and a transition metal luminescent center is provided. The emitter layer is fabricated by co-sputtering an Al target and a transition metal target over a deposition surface of a semiconductor substrate so as to form an amorphous AlN:TM film on the deposition surface. The RF magnetron sputtering is performed in a nitrogenous atmosphere, at room temperature, under vacuum. The amorphous film is activated by annealing at or above about 1250 K.
In accordance with yet another embodiment of the present invention, an alternating current thin film electroluminescent device is provided. The ACTFEL device comprises an AC power source and an emitter layer positioned between a pair of electrode layers. At least one of the pair of electrode layers is transparent to visible light of a selected wavelength. The AC power source is connected across the pair of electrode layers. The emitter layer comprises a non-conductive amorphous alloy comprising aluminum nitride and an rare earth luminescent center. The emitter layer and the pair of electrode layers are arranged such that, upon activation of the AC power source, an electric field is created between the electrode layers across the emitter layer. The aluminum nitride and the rare earth luminescent center are provided in proportions selected such that the electric field causes emission of visible light of the selected wavelength from the emitter layer.
In accordance with yet another embodiment of the present invention, a method of fabricating an alternating current thin film electroluminescent device is provided. According to the method, a non-conductive amorphous film emitter layer comprising aluminum nitride and a rare earth luminescent center is prepared by co-sputtering an Al target and a rare earth target in a nitrogenous atmosphere at room temperature under vacuum. The emitter layer is positioned between a pair of electrode layers. An AC power source is connected across the pair of electrode layers. The emitter layer and the pair of electrode layers are arranged such that, upon activation of the AC power source, an electric field is created between the electrode layers across the emitter layer. The aluminum nitride and the rare earth luminescent center are provided in proportions selected such that the electric field causes emission of visible light of the selected wavelength from the emitter layer. The emitter layer may be prepared by maintaining the emitter layer near room temperature, whereby heated activation of the emitter layer is unnecessary.
In accordance with yet another embodiment of the present invention, a method of fabricating an amorphous luminescent emitter layer comprising aluminum nitride and a rare earth luminescent center is provided. According to the method, the emitter layer is prepared by co-sputtering an Al target and a rare earth target over a deposition surface of a substrate so as to form an amorphous AlN:RE film emitter layer on the deposition surface. The co-sputtering is performed in a nitrogenous atmosphere, at room temperature, under vacuum. The emitter layer may be prepared by maintaining the emitter layer near room temperature, whereby heated activation of the emitter layer is unnecessary.
Accordingly, it is an object of the present invention to provide high performing, efficient, inexpensive, and readily producible luminescent emitter layers. Other objects of the present invention will be apparent in light of the description of the invention embodied herein.
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Kordesch Martin E.
Richardson Hugh
Brewster William M.
Chaudhuri Olik
Dinsmore & Shohl LLP
Ohio University
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