SEMICONDUCTOR LIGHT EMITTING DEVICE WITH PROTRUSIONS TO IMPROVE EXTERNAL EFFICIENCY AND CRYSTAL GROWTH

• US 20100197055A1
• Filed: 03/03/2010
• Published: 08/05/2010
• Est. Priority Date: 08/19/2003
• Status: Active Grant

• Current Assignee: Hisanori Tanaka, Yasunobu Hosokawa, Yuuki Shibutani
• Original Assignee: Hisanori Tanaka, Yasunobu Hosokawa, Yuuki Shibutani
• Inventors: Shibutani, Yuuki, Hosokawa, Yasunobu, TANAKA, Hisanori
• Granted Patent: US 8,119,534 B2
• Time in Patent Office: Days
• US Class Current: 438/29
• CPC Class Codes: H01L 21/0237 Materials
• CPC Class Codes: H01L 21/0242 Crystalline insulating materials
• CPC Class Codes: H01L 21/0243 Surface structure
• CPC Class Codes: H01L 21/02433 Crystal orientation
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02647 Lateral overgrowth
• CPC Class Codes: H01L 21/02658 Pretreatments cleaning in general H01L21/02041
• CPC Class Codes: H01L 2224/48095 Kinked
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/13091 Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding
• CPC Class Codes: H01L 2933/0083 Periodic patterns for optical field-shaping in or on the semiconductor body or semiconductor body package, e.g. photonic bandgap structures
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/22 : Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/38 : with a particular shape

Abstract

A substrate has at least one recess and/or protrusion formed in and/or on a surface thereof so as to scatter or diffract light generated in an active layer. The recess and/or protrusion is formed in such a shape that can reduce crystalline defects in semiconductor layers.

Claims

1-27. -27. (canceled)

28. A method of manufacturing a substrate for a light emitting device that has a plurality of protrusions on a surface of the substrate, comprising:

a first step of etching a part of the substrate with a protective film provided on the substrate and forming protrusions having side faces; and

a second step of exposing and etching the side faces and at least a part of top faces of said protrusions, so as to make an inclination angle of the side faces on a lower side larger than an inclination angle of the side faces on an upper side.

29. The method of manufacturing a substrate for the light emitting device according to claim 28, wherein said second step is followed by a third step where the side faces and at least a part of the top faces of said protrusions are exposed and etched, so as to turn the side faces into curved surfaces.

30. The method of manufacturing a substrate for the light emitting device according to claim 29, wherein the top faces of said protrusions are circular.

31. The method of manufacturing a substrate for the light emitting device according to claim 28, wherein the protective film is removed by the etching in said first step.

32. The method of manufacturing a substrate for the light emitting device according to claim 28, wherein a plurality of notches are formed on the side faces of said protrusions in said first step, and width of the notches in the side faces is larger on a lower side than on an upper side and/or the number of the notches is larger on a lower side than on an upper side.

33. A method of manufacturing a substrate for a light emitting device that has a plurality of protrusions on a surface of the substrate, comprising:

a first step of etching a part of the substrate with a protective film provided on the substrate and forming protrusions having side faces; and

a second step of exposing and etching the side faces and at least a part of top faces of said protrusions, so as to make an inclination angle of the side faces on a lower side larger than an inclination angle of the side faces on an upper side and to make an inclination angle of the side faces as a whole smaller than an inclination angle of the side faces as a whole in the first step.

34. The method of manufacturing a substrate for the light emitting device according to claim 33, wherein the protective film is removed by the etching in said first step.

35. The method of manufacturing a substrate for the light emitting device according to claim 33, wherein the protective film is removed by the etching in said second step.

36. The method of manufacturing a substrate for the light emitting device according to claim 35, wherein, in said second step, an inclination angle θ

_m2 of the side faces as a whole is smaller than an inclination angle θ

_m1 of the side faces as a whole in the first step.

37. The method of manufacturing a substrate for the light emitting device according to claim 35, wherein said protrusions have circular, triangular, parallelogram or hexagonal profile in plan view.

38. The method of manufacturing a substrate for the light emitting device according to claim 35, wherein said second step is followed by a third step where the side faces and at least a part of the top faces of said protrusions are exposed and etched, so as to turn the side faces into curved surfaces.

39. The method of manufacturing a substrate for the light emitting device according to claim 38, wherein the protective film is removed by the etching either in said first step or said second step.

40. A method of manufacturing a substrate for a light emitting device that has a plurality of protrusions on a surface of the substrate where semiconductor layers of the light emitting device is formed, comprising:

a first step of etching a part of the substrate with a protective film provided on the substrate and forming protrusions having side faces that has an inclination angle θ

_m1 as a whole; and

a second step of exposing and etching the side faces and at least a part of top faces of said protrusions, so as to make an inclination angle θ

_m2 of the side faces as a whole smaller than the inclination angle θ

_m1.

41. The method of manufacturing a substrate for the light emitting device according to claim 40, wherein the protective film is removed by the etching in said first step.

42. The method of manufacturing a substrate for the light emitting device according to claim 40, wherein the protective film is removed and exposed protrusions are etched in said second step.

43. The method of manufacturing a substrate for the light emitting device according to claim 40, wherein said second step is followed by a third step where the side faces and at least a part of the top faces of said protrusions are exposed and etched, so as to make an inclination angle θ

_m3 of the side faces as a whole smaller than the inclination angle θ

_m2.

44. The method of manufacturing a substrate for the light emitting device according to claim 43, wherein, in said third step, the side faces are turned into curved surfaces.

45. The method of manufacturing a substrate for the light emitting device according to claims 40, wherein said protrusions have circular, triangular, parallelogram or hexagonal profile in plan view.

46. The method of manufacturing a substrate for the light emitting device according to claim 45, wherein said substrate is a sapphire substrate having C plane (0001).

47. A method for manufacturing a light emitting device, wherein a nitride semiconductor structure of a light emitting device is formed on a protrusions-formed surface of a substrate manufactured by the method according to claim 46.