Alternating current light-emitting device and fabrication method thereof

• US 20080106212A1
• Filed: 02/26/2007
• Published: 05/08/2008
• Est. Priority Date: 11/08/2006
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Industrial Technology Research Institute
• Inventors: Yeh, Wen-Yung, Yen, Hsi-Hsuan
• Granted Patent: US 7,855,388 B2
• Time in Patent Office: Days
• US Class Current: 315/192
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H05B 45/30 Driver circuits
• CPC Class Codes: H05B 45/40 Details of LED load circuits
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

An alternating current light-emitting device includes a substrate, a plurality of microdie light-emitting elements formed on the substrate, a rectifying element-dedicated member formed on a surface of a portion of microdie light-emitting elements, a rectifying unit formed on the rectifying element-dedicated member and provided with at least four rectifying elements forming a Wheatstone bridge circuit, and an electrically conductive structure electrically connecting the rectifying elements and the microdie light-emitting elements. With the rectifying unit being formed on the rectifying element-dedicated member, the rectifying elements are highly tolerant of reverse bias and feature low starting forward bias. Also, the present invention provides a method for fabricating an alternating current light-emitting device.

Claims

1. An alternating current light-emitting device, at least comprising:

a substrate;

a plurality of microdie light-emitting elements formed on the substrate, each of the microdie light-emitting elements at least being provided with an active layer and an electrically conductive terminal;

a rectifying element-dedicated member formed on a surface of a portion of the microdie light-emitting elements;

a rectifying unit formed on the rectifying element-dedicated member, provided with at least four rectifying elements forming a Wheatstone bridge circuit, and adapted to provide rectification and output a direct current signal to each of the microdie light-emitting elements; and

an electrically conductive structure for electrically connecting the rectifying elements and the microdie light-emitting elements.

2. The alternating current light-emitting device of claim 1, wherein the substrate is one of a chip and an insulated substrate.

3. The alternating current light-emitting device of claim 1, wherein the active layer is a light-emitting activity layer.

4. The alternating current light-emitting device of claim 1, wherein the electrically conductive terminal is an Ohmic electrode.

5. The alternating current light-emitting device of claim 1, wherein the rectifying element-dedicated member is a rectifying element-dedicated layer formed by one of epitaxy and deposition.

6. The alternating current light-emitting device of claim 5, wherein the rectifying element-dedicated layer is made of a semiconductive material AlGaN.

7. The alternating current light-emitting device of claim 1, wherein the rectifying element-dedicated member is a rectifying element-dedicated region formed by doping a dopant into the substrate by one of ion implantation and diffusion.

8. The alternating current light-emitting device of claim 7, wherein the dopant is a n-type dopant.

9. The alternating current light-emitting device of claim 1, wherein connection of the microdie light-emitting elements is one selected from the group consisting of series connection, parallel connection, and both.

10. The alternating current light-emitting device of claim 9, wherein each of the microdie light-emitting elements emits light with one of identical wavelengths and different wavelengths.

11. The alternating current light-emitting device of claim 1, wherein the electrically conductive structure is one selected from the group consisting of an electrically conductive bridge, a metallic wire-bonding structure, and a transparent metal oxide layer capable of electrical conduction.

12. The alternating current light-emitting device of claim 1, wherein each of the microdie light-emitting elements comprises a buffer layer, an n-type semiconductor, an active layer, and a p-type semiconductor.

13. The alternating current light-emitting device of claim 1, wherein the microdie light-emitting elements are disposed in a matrix.

14. The alternating current light-emitting device of claim 1, wherein the rectifying element is a Schottky diode.

15. A method for fabricating an alternating current light-emitting device, at least comprising the steps of:

providing a substrate;

forming on the substrate a plurality of microdie light-emitting elements at least provided with one active layer;

forming on a surface of a portion of the microdie light-emitting elements a rectifying element-dedicated layer;

forming on the rectifying element-dedicated layer a rectifying unit provided with at least four rectifying elements forming a Wheatstone bridge circuit;

forming a groove by etching so as to insulate the microdie light-emitting elements and the rectifying elements from one another;

forming an electrically conductive terminal on each of the microdie light-emitting elements; and

forming an electrically conductive structure for electrically connecting the rectifying elements and the electrically conductive terminals of the microdie light-emitting elements.

16. The method for fabricating an alternating current light-emitting device of claim 15, further comprising the steps of defining regions of the rectifying elements on a surface of the rectifying element-dedicated layer by etching before forming the rectifying unit, and removing a residual portion of the rectifying element-dedicated layer thoroughly.

17. The method for fabricating an alternating current light-emitting device of claim 15, further comprising the steps of enclosing a periphery of the microdie light-emitting elements with a protective layer, and removing a portion of the protective layer so as to form the plurality of electrically conductive terminals penetrating the protective layer.

18. The method for fabricating an alternating current light-emitting device of claim 17, wherein the protective layer is made of a dielectric material.

19. The method for fabricating an alternating current light-emitting device of claim 18, wherein the dielectric material is one of SiO_x and SiN_x.

20. The method for fabricating an alternating current light-emitting device of claim 15, wherein the electrically conductive terminal is an Ohmic electrode.

21. The method for fabricating an alternating current light-emitting device of claim 15, wherein each of the rectifying elements is a Schottky diode.

22. The method for fabricating an alternating current light-emitting device of claim 15, wherein the electrically conductive structure is one selected from the group consisting of an electrically conductive bridge, a metallic wire-bonding structure, and a transparent metal oxide layer capable of electrical conduction.

23. The method for fabricating an alternating current light-emitting device of claim 15, wherein the rectifying element-dedicated layer is made of a semiconductive material AlGaN.

24. The method for fabricating an alternating current light-emitting device of claim 15, wherein the rectifying element-dedicated layer is formed by one of epitaxy and deposition.

25. The method for fabricating an alternating current light-emitting device of claim 15, wherein the electrically conductive terminal is formed by vapor deposition.

26. A method for fabricating an alternating current light-emitting device, at least comprising the steps of:

providing a substrate;

forming on the substrate a plurality of microdie light-emitting elements at least provided with one active layer;

doping a dopant into a surface of a portion of the microdie light-emitting elements to form a rectifying element-dedicated region by decreasing doping concentration;

forming on the rectifying element-dedicated region a rectifying unit provided with at least four rectifying elements forming a Wheatstone bridge circuit;

forming a groove by etching so as to insulate the microdie light-emitting elements and the rectifying elements from one another;

forming an electrically conductive terminal on each of the microdie light-emitting elements; and

forming an electrically conductive structure for electrically connecting the rectifying elements and the electrically conductive terminals of the microdie light-emitting elements.

27. The method for fabricating an alternating current light-emitting device of claim 26, further comprising the steps of defining regions of the rectifying elements on the rectifying element-dedicated region by etching before forming the rectifying unit.

28. The method for fabricating an alternating current light-emitting device of claim 26, further comprising the steps of enclosing a periphery of the microdie light-emitting elements with a protective layer, and removing a portion of the protective layer so as to form the plurality of electrically conductive terminals penetrating the protective layer.

29. The method for fabricating an alternating current light-emitting device of claim 28, wherein the protective layer is made of a dielectric material.

30. The method for fabricating an alternating current light-emitting device of claim 29, wherein the dielectric material is one of SiO_x and SiN_x.

31. The method for fabricating an alternating current light-emitting device of claim 26, wherein the electrically conductive terminal is an Ohmic electrode.

32. The method for fabricating an alternating current light-emitting device of claim 26, wherein each of the rectifying elements is a Schottky diode.

33. The method for fabricating an alternating current light-emitting device of claim 26, wherein the electrically conductive structure is one selected from the group consisting of an electrically conductive bridge, a metallic wire-bonding structure, and a transparent metal oxide layer capable of electrical conduction.

34. The method for fabricating an alternating current light-emitting device of claim 26, wherein the dopant doped into the rectifying element-dedicated region is an n-type dopant.

35. The method for fabricating an alternating current light-emitting device of claim 26, wherein the electrically conductive terminal is formed by vapor deposition.

36. The method for fabricating an alternating current light-emitting device of claim 26, wherein the rectifying element-dedicated region is formed by being doped with the dopant by one of ion implantation and diffusion.