Semiconductor light emitting element and method for manufacturing the same

• US 20030218172A1
• Filed: 04/04/2003
• Published: 11/27/2003
• Est. Priority Date: 04/05/2002
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Abe, Hirohisa, Konno, Kuniaki, Sugawara, Hideto, Watanabe, Yukio
• Granted Patent: US 6,956,241 B2
• Time in Patent Office: Days
• US Class Current: 257/72
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• 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 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/10155 being other than a cuboid
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/16 with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
• 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

Abstract

A high-luminance light emitting element is manufactured by a method comprising: forming a light emitting layer on a first surface of a GaP substrate including the first surface and a second surface opposed to the first surface and having an area smaller than the first area, the light emitting layer emitting light of a wavelength λ permitted to pass through the GaP substrate; forming a plurality of side surfaces on the GaP substrate to be respectively aslant by substantially the same angle to become narrower toward the second surface; and forming a plurality of depressions and protrusions as high as 0.1 λ to 3 λ on the side surfaces.

Claims

1. A semiconductor light emitting element comprising:

a light emitting layer for emitting light of a wavelength λ

by current injection; and

a GaP substrate transparent to light of the wavelength λ and

having;

a first surface on which the light emitting layer is formed;

a second surface opposed to the first surface and having an area smaller than the first surface; and

side surfaces individually being aslant to become narrower toward the second surface and permitting part of light from the light emitting layer to be extracted externally therethrough, said side surfaces having a plurality of depressions and protrusions along outer surfaces thereof.

2. A semiconductor light emitting element according to claim 1 wherein the side surfaces are respectively aslant by substantially the same angle to become narrower toward the second surface.

3. A semiconductor light emitting element according to claim 1 wherein the depressions and protrusions have a height in a range from a lower limit equal to or higher than 0.1 λ

to an upper limit equal to or lower than 3 λ

.

4. A semiconductor light emitting element according to claim 1 wherein the GaP substrate is an off-axis (100) GaP substrate with the off-axis angle of θ

(5°

≦

θ

≦

20°

) along the [011] direction.

5. A semiconductor light emitting element according to claim 1 wherein the second surface is (100) oriented.

6. A semiconductor light emitting element according to claim 1 wherein the light emitting layer includes an InGaAlP layer.

7. A method for manufacturing a semiconductor light emitting element, comprising:

forming a light emitting layer on a first surface of a GaP substrate including the first surface and a second surface opposed to the first surface and having an area smaller than the first area, said light emitting layer emitting light of a wavelength λ

permitted to pass through the GaP substrate;

forming a plurality of side surfaces on the GaP substrate to be respectively aslant by substantially the same angle to become narrower toward the second surface; and

forming a plurality of depressions and protrusions on the side surfaces by regrowing GaP thereon by MOCVD using source material gases of a group V source material including phosphorus and a group III source material including gallium at a growth temperature in a range from a lower limit equal to or higher than 350°

C. to an upper limit equal to or lower than 700°

C.

8. A method for manufacturing a semiconductor light emitting element according to claim 7 wherein the depressions and protrusions have a height in a range from a lower limit equal to or higher than 0.1 λ

to an upper limit equal to or lower than 3 λ

.

9. A method for manufacturing a semiconductor light emitting element according to claim 7 wherein the GaP substrate is an off-axis (100) GaP substrate with the off-axis angle of θ

(5°

≦

θ

≦

20°

) along the [011] direction.

10. A method for manufacturing a semiconductor light emitting element, comprising:

forming a light emitting layer on a first surface of a GaP substrate including the first surface and a second surface opposed to the first surface and having an area smaller than the first surface, said light emitting layer emitting light of a wavelength λ

permitted to pass through the GaP substrate;

forming a plurality of side surfaces on the GaP substrate to be respectively aslant by substantially the same angle to become narrower toward the second surface; and

forming a plurality of depressions and protrusions on the side surfaces by thermal decomposition of the side surfaces of the GaP substrate in a mixed gas of a group V source material including phosphorus with hydrogen, or hydrogen, used as the atmospheric gas, which is controlled in temperature in a range from a lower limit equal to or higher than 350°

C. to an upper limit equal to or lower than 1000°

C., and by removing droplets of gallium as residues of the thermal decomposition by etching with an etchant.

11. A method for manufacturing a semiconductor light emitting element according to claim 10 wherein the depressions and protrusions have a height in a range from a lower limit equal to or higher than 0.1 λ

to an upper limit equal to or lower than 3 λ

.

12. A method for manufacturing a semiconductor light emitting element according to claim 10 wherein the GaP substrate is an off-axis (100) GaP substrate with the off-axis angle of θ

(5°

≦

θ

≦

20°

) along the [011] direction.

13. A method for manufacturing a semiconductor light emitting element, comprising:

forming a light emitting layer on a first surface of a GaP substrate including the first surface and a second surface opposed to the first surface and having an area smaller than the first surface, said light emitting layer emitting light of a wavelength λ

permitted to pass through the GaP substrate;

forming a plurality of side surfaces on the GaP substrate to be respectively aslant by substantially the same angle to become narrower toward the second surface; and

forming a plurality of depressions and protrusions on the side surfaces by forming a metal layer of any of Al, Ti, Sn, Ag and Au by vapor deposition of sputtering and removing the metal layer by etching with an etchant.

14. A method for manufacturing a semiconductor light emitting element according to claim 13 wherein the depressions and protrusions have a height in a range from a lower limit equal to or higher than 0.1 λ

to an upper limit equal to or lower than 3 λ

.

15. A method for manufacturing a semiconductor light emitting element, comprising:

forming a light emitting layer on a first surface of a GaP substrate including the first surface and a second surface opposed to the first surface and having an area smaller than the first surface, said light emitting layer emitting light of a wavelength λ

permitted to pass through the GaP substrate;

forming a plurality of side surfaces on the GaP substrate to be respectively aslant by substantially the same angle to become narrower toward the second surface; and

forming a plurality of depressions and protrusions on the side surfaces by blasting the side surfaces with particles containing alumina adjusted in diameter in a range from a smaller limit equal to or larger than 2 μ

m to a larger limit equal to or smaller than 3 μ

m, and etching them with an etchant.

16. A method for manufacturing a semiconductor light emitting element according to claim 15 wherein the depressions and protrusions have a height in a range from a lower limit equal to or higher than 0.1 λ

to an upper limit equal to or lower than 3 λ

.

17. A method for manufacturing a semiconductor light emitting element, comprising:

forming a light emitting layer on a first surface of a GaP substrate including the first surface and a second surface opposed to the first surface and having an area smaller than the first surface, said light emitting layer emitting light of a wavelength λ

permitted to pass through the GaP substrate;

forming a plurality of side surfaces on the GaP substrate to be respectively aslant by substantially a same angle to become narrower toward the second surface by using a dicing blade having depressions and protrusions on an outer surface thereof; and

forming a plurality of depressions and protrusions on the side surfaces by etching them with an etchant.

18. A method for manufacturing a semiconductor light emitting element, comprising:

forming a light emitting layer on a first surface of a GaP substrate including the first surface and a second surface opposed to the first surface and having an area smaller than the first surface, said light emitting layer emitting light of a wavelength λ

permitted to pass through the GaP substrate;

forming a plurality of side surfaces on the GaP substrate to be respectively aslant by substantially a same angle to become narrower toward the second surface; and

forming a plurality of depressions and protrusions on the side surfaces by etching with an etchant while irradiating halogen light.

19. A method for manufacturing a semiconductor light emitting element, comprising:

forming a light emitting layer on a first surface of a GaP substrate including the first surface and a second surface opposed to the first surface and having an area smaller than the first surface, said light emitting layer emitting light of a wavelength λ

permitted to pass through the GaP substrate;

forming a plurality of side surfaces on the GaP substrate to be respectively aslant by substantially a same angle to become narrower toward the second surface; and

forming a plurality of depressions and protrusions on the side surfaces by heating them to a softening point of the GaP crystal and pressing a die defining depressions and protrusions onto the heated side surfaces.