Method for fabricating white-light-emitting flip-chip diode having silicon quantum dots

The present invention relates to fabricating a diode; more particularly, relates to emitting a white light of evenly mixed colorful lights through a film having silicon quantum dots.

A prior art, “A diode emitting a white light and a fabrication method thereof”, is proclaimed in Taiwan where the diode comprises

a first conductive electrode;

a base of GaAs, GaP, Si or 3C-sic electrically contacted with the first conductive electrode;

a first emitting part, made of compounds of AlGaInP, having a first bondage layer, an active layer and a second bondage layer sequentially formed on the base;

A buffer layer made of B x Ga (1-x) P and In y Ga (1-y) N, 0<x<1 and 0<y<1, on the second bondage layer.

a second emitting part, made of compounds of AlGaInN, having a first bondage layer, an active layer and a second bondage layer sequentially formed on the first buffer layer; and

a second conductive electrode electrically contacted with the second bondage layer of the second emitting part.

When a potential difference is externally added between the second conductive electrode and the first conductive electrode, a current is obtained. The current flows through the second conductive electrode, the buffer layer and the first conductive electrode, where the first conductive electrode emits a light of a first wavelength; the second conductive electrode emits a light of a second wavelength; and a white light is obtained by mixing the light of the first wavelength and the light of the second wavelength.

Although the above prior art can generate a white light by mixing the light of the first wavelength and the light of the second wavelength, the structure is complex and the white light obtained is sometime polarized toward a blue light or a yellow light. Hence, the prior art does not fulfill users' requests on actual use.

The main purpose of the present invention is to emit a white light of colorful lights evenly mixed, where the colorful lights includes an ultra blue-violet light, which is emitted from a flip-chip diode; and a green light, a yellow light and a red light, which are emitted from a luminescent film material by exciting the silicon (Si) quantum dots of a film material with the ultra blue-violet light; and where the colorful lights are processed with refractions and diffractions through a transparent substrate.

To achieve the above purpose, the present invention is a method for fabricating a white-light-emitting flip-chip diode having Si quantum dots, where evenly embedded Si quantum dots are formed through a chemical vapor deposition or a sol-gel process in a luminescent film material; then the luminescent film material is coated on a transparent substrate; and, finally, a flip-chip diode is sticked to the luminescent film material on a light-extracting surface of the flip-chip diode for emitting a white light of evenly mixed colorful lights. Accordingly, a novel method for fabricating a white-light-emitting flip-chip diode having Si quantum dots is obtained.

The present invention will be better understood from the following detailed description of the preferred embodiment according to the present invention, taken in con junction with the accompanying drawings, in which

FIG. 1 is a view showing step (a) of a preferred embodiment according to the present invention;

FIG. 2 is a view showing step (b);

FIG. 3 is a view showing step (c);

FIG. 4 is a view showing step (d); and

FIG. 5 is a view showing a state of use.

The following description of the preferred embodiment is provided to understand the features and the structures of the present invention.

Please refer to FIG. 1 till FIG. 4 , which are views showing step (a) till step (d) of a preferred embodiment according to the present invention. As shown in the figures, the present invention is a method for fabricating a white-light-emitting flip-chip diode having silicon (Si) quantum dots, comprising the following steps:

Step (a): Obtaining a transparent substrate 1 . The transparent substrate 1 is a conductive glass of indium tin oxide, a quartz or a sapphire.

Step (b): Obtaining a film material 22 of SiO 2 , Si 3 N 4 or SiC with evenly embedded Si quantum dots 21 of granular sizes between 1 and 10 nanometers formed through an atmospheric pressure chemical vapor deposition or a plasma-enhanced chemical vapor deposition, operated under a temperature between 100 and 1000 Celsius degrees or a sol-gel process to obtain a luminescent film material having Si quantum dots 21 , which has a thickness between 1 and 100 micrometers.

Step (C): Coating the luminescent film material having Si quantum dots 21 on the transparent substrate 1 .

Step (d) Obtaining a flip-chip diode emitting ultra blue-violet light 3 to be pasted with a transparent adhesive 4 on a light-extracting surface 31 (located on an upper surface of a transparent sapphire substrate of the flip-chip diode) to be adhered with the luminescent film material having Si quantum dots 2 . The wavelength range of the ultra blue-violet light 3 is about 200-400 nm (nanometers).

Hence, a novel method for fabricating a white-light-emitting flip-chip diode having Si quantum dots is obtained.

Please refer to FIG. 5 , which is a view showing a state of use. As shown in the figure, when using the present invention, a leading wire 31 is contacted with a Si substrate 32 ; and, an ultra blue-violet light is emitted by the flip-chip diode by using a connection to an outside power supply. The ultra blue-violet light generated by the flip-chip diode 3 and the green light, yellow light and red light generated by exciting the Si quantum dots in the luminescent film material with the ultra blue-violet light, are processed with refractions and diffractions through the transparent substrate 1 for emitting a white light by evenly mixing colorful lights.

To sum up, the present invention is a method for fabricating a white-light-emitting flip-chip diode having Si quantum dots, where an ultra blue-violet light, which is emitted from a flip-chip diode, and a green light, a yellow light and a red light, which are emitted from a film material by exciting the Si quantum dots of the film material with the ultra blue-violet light, are processed with refractions and diffractions through a transparent substrate for emitting a white light of the above colorful lights evenly mixed.

The preferred embodiment herein disclosed is not intended to unnecessarily limit the scope of the invention. Therefore, simple modifications or variations belonging to the equivalent of the scope of the claims and the instructions disclosed herein for a patent are all within the scope of the present invention.