Sapphire monocrystal, semiconductor laser diode using the same for substrate, and method for manufacturing the same

• US 20040109486A1
• Filed: 05/22/2003
• Published: 06/10/2004
• Est. Priority Date: 02/29/1996
• Status: Active Grant

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Corporation
• Inventors: Kinoshita, Hiroyuki, Umehara, Motohiro
• Granted Patent: US 6,819,693 B2
• Time in Patent Office: Days
• US Class Current: 372/45
• CPC Class Codes: C30B 29/20 Aluminium oxides
• CPC Class Codes: C30B 33/00 After-treatment of single crystals or homogeneous polycrystalline material with defined structure C30B31/00 takes precedence
• CPC Class Codes: G02B 1/02 made of crystals, e.g. rock-salt, semi-conductors G02B1/08 takes precedence
• CPC Class Codes: H01S 5/0202 Cleaving
• CPC Class Codes: H01S 5/0213 Sapphire, quartz or diamond based substrates
• CPC Class Codes: H01S 5/0422 with n- and p-contacts on the same side of the active layer
• CPC Class Codes: H01S 5/3202 grown on specifically orientated substrates, or using orientation dependent growth
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP

Abstract

The present invention relates to a sapphire monocrystal body to be used as the substrate of the thin growth for the semiconductor or the like as electronic parts or component parts, and to a monocrystal sapphire substrate. The invention also relates to a method for working the same. The invention utilizes that the cleavage plane of the plane R of the sapphire monocrystal body has a smooth plane high in surface precision and is easier to cleave. For an easier dividing operation, by cleaving, of the substrate after the formation of the element such as semiconductor element, functional element, the reference plane substantially parallel or vertical to the plane R is provided on the periphery of the substrate, so as to make an index for controlling the plane R in the cleavage division. A method applies forming linear crack parallel or vertical to the reference plane of the substrate, having microcrack line as a starting point to develop the crack in the thickness direction.

In the laser diode under the invention, the monocrystal sapphire substrate which forms the semiconductor multilayer is cleaved, divided along the plane R to form the cleaved plane connected with the semiconductor multilayer and the substrate. Since the cleaved plane of the semiconductor multilayer is an extremely smooth plane, the cleaved plane can be used for reflection plane for laser resonator use of the semiconductor multilayer.

Claims

1. A sapphire monocrystal body comprising a cleavage plane parallel to a plane R of the crystal on the surface.

2. A sapphire monocrystal body according to claim 1, wherein said monocrystal body is a sapphire tool comprising a sharp edge to be formed by the working plane and said cleavage plane.

3. A sapphire monocrystal body according to claim 1, wherein said monocrystal body is a monocrsytal sapphire substrate comprising said cleavage plane on the side face.

4. A sapphire monocrystal body according to claim 1, wherein said monocrystal body has elements such as semiconductor element, functional element and the like on the major plane, and has said cleavage plane on the side face.

5. A monocrystal body according to claim 1, wherein said monocrystal body is a monocrystal sapphire substrate of a laser diode comprising a semiconductor multilayer for laser light emitting use formed on the major plane, and said cleavage plane connected with the cleaved plane of the multilayer on the side face.

6. A sapphire monocrystal plate, wherein a working reference plane parallel or vertical to the plane R of the crystal is formed on the peripheral edge portion of said sapphire monocrystal plate, and the working reference plane makes an index for forming on the plate surface a microcrack line parallel to the plane R.

7. A sapphire monocrystal plate according to claim 6, wherein said working reference plane is in the angle range within ±

10°

from the orientation completely parallel or vertical to the plane R.

8. A sapphire monocrystal plate according to claim 6, wherein said monosapphire crystal plate is a monocrystal sapphire substrate wherein elements such as semiconductor element, functional element or the like is to be formed on the major plane, and is to be formed said cleavage plane on the side face after the formation of the element.

9. A method of forming a cleavage plane of the sapphire monocrystal plate comprising forming microcrack line parallel to the plane R of the crystal on the plate plane of said sapphire monocrystal plate, and subsequently giving mechanical or thermal stressing on the plate surface near the microcrack line, thereby growing the cracks and cleaving along the plane R.

10. A method of forming a cleavage plane according to claim 9, further comprising previously forming the reference plane parallel or vertical to the R plate of the crystal on the peripheral edge portion of said sapphire monocrystal plate, forming vertically or in parallel to the microcrack line on the working reference plane in the formation of the cleavage plane.

11. A semiconductor laser diode, wherein a semiconductor multilayer for forming the laser element is provided on the major plane of the monocrystal sapphire substrate, two opposite reflection end faces comprising the resonator of the laser beam in the multilayer is a cleavage plane connected to the cleavage plane along the plane R of the crystal of said sapphire monocrystal substrate.

12. A semiconductor laser diode according to claim 11, wherein said semiconductor multilayer is a multilayer of a gallium nitride system compound semiconductor of double hetero junction structure, the major plane of the monocrystal sapphire substrate is substantially parallel to the plane A, said cleavage plane of the substrate is comprised by 2.5 through 3.5°

from the plane R of the sapphire crystal on the major plane and also is inclined in the direction from 59.5 through 60.5°

from the plane C.

13. A method of manufacturing a semiconductor laser diode comprising forming semiconductor multilayer of the laser element on the major plane of the monocrystal sapphire substrate, then cleaving the monocrystal substrate and the multilayer along the plane R of the crystal, thereby making both the side cleavage planes of the multilayer two opposite reflection end planes for composing the reasoner of the laser beam.

14. A method of manufacturing semiconductor a laser diode comprising forming a semiconductor multilayer of the laser element on the major plane of the monocrystal sapphire substrate, then forming microcrack line parallel to the plane R of the crystal on the reverse plane of the sapphire monocrystal plane, subsequently giving mechanical or thermal stressing to the plate plane near the microcrack line, thereby growing the cracks and cleaving the monocrystal substrate and the mutiplayer along the plane R, and making both the side cleavage planes of the multilayer two opposite reflection end faces for composing the reasoner of the laser beam.

15. A method of manufacturing of a semiconductor laser diode according to claim 14 further comprising forming the working reference plane parallel to or vertical to the plane R of the crystal on the peripheral edge portion on said monocrystal sapphire substrate in advance, thereby forming the microcrack line vertical or parallel to the reference plane when forming the cleavage plane.

16. A method of manufacturing a semiconductor laser diode comprising forming a multilayer of gallium nitride system compound semiconductor of double hetero junction structure of a laser element on the major plane of said monocrystal sapphire substrate substantially parallel to the plane A by the major plane, then forming the microcrack line in a direction inclined by 2.5 through 3.5°

from the plane R of the crystal, and also inclined by 59.5 through 60.5°

from the plane C on the reverse plane of said sapphire monocrystal plate, subsequently giving mechanical or thermal stressing to the plate plane near the microcrack line, thereby growing the cracks, cleaving the monocrystal substrate and the multilayer, and making both the cleaved planes of the multilayer two opposite reflection end faces for composing the resonator of the laser beam.