Surface emitting laser element and optical device

• US 10,224,692 B2
• Filed: 12/05/2017
• Issued: 03/05/2019
• Est. Priority Date: 01/12/2017
• Status: Active Grant

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: Onishi, Dai, Yamamoto, Masashi, Takamizu, Daiju
• Primary Examiner(s): King, Joshua
• Application Number:
  US15/831,848
• Publication Number:
  US 20180198255A1
• Time in Patent Office: 455 Days
• CPC Class Codes: H01S 2301/176 Specific passivation layers on surfaces other than the emission facet
• CPC Class Codes: H01S 5/02234 Resin-filled housings; the housings being made of resin
• CPC Class Codes: H01S 5/02345 Wire-bonding
• CPC Class Codes: H01S 5/0262 Photo-diodes, e.g. transceiver devices, bidirectional devices H01S5/0265 takes precedence
• CPC Class Codes: H01S 5/04254 characterised by the shape
• CPC Class Codes: H01S 5/04256 characterised by the configuration
• CPC Class Codes: H01S 5/1071 Ring-lasers
• CPC Class Codes: H01S 5/183 having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL]
• CPC Class Codes: H01S 5/18313 by oxidizing at least one of the DBR layers
• CPC Class Codes: H01S 5/18344 characterized by the mesa, e.g. dimensions or shape of the mesa
• CPC Class Codes: H01S 5/2205 comprising special burying or current confinement layers
• CPC Class Codes: H01S 5/423 having a vertical cavity

Abstract

A surface emitting laser element includes a first distribution Bragg reflector (DBR) layer having a first conductivity type; a second DBR layer having a second conductivity type opposite to the first conductivity type; an active layer located between the first DBR layer and the second DBR layer; an insulating layer formed over the second DBR layer; and a surface conductive layer formed over the insulating layer. In the surface emitting laser element, a first opening, which exposes the insulating layer and overlaps with the active layer when viewed in a thickness direction of the first DBR layer, is formed in the surface conductive layer, and the first opening extends when viewed in the thickness direction.

Claims

1. A surface emitting laser element, comprising:

a first distribution Bragg reflector (DBR) layer having a first conductivity type;

a second DBR layer having a second conductivity type opposite to the first conductivity type;

an active layer located between the first DBR layer and the second DBR layer;

an insulating layer formed over the second DBR layer; and

a surface conductive layer formed over the insulating layer,

wherein a first opening, which exposes the insulating layer and overlaps with the active layer when viewed in a thickness direction of the first DBR layer, is formed in the surface conductive layer, and the first opening extends and has an annular shape when viewed in the thickness direction,

wherein an additional opening, which exposes the insulating layer and overlaps with the active layer when viewed in the thickness direction of the first DBR layer, is formed in the surface conductive layer, and the additional opening has an annular shape and is connected to the first opening.

2. The surface emitting laser element of claim 1, wherein the surface conductive layer comprises:

a first surface portion defining a portion of the first opening; and

a first contact portion located between the first surface portion and the second DBR layer, and electrically connected to the first surface portion and the second DBR layer.

3. The surface emitting laser element of claim 1, wherein the second DBR layer comprises a DBR layer surface that is located on an opposite side from where the first DBR layer is located, and

wherein a first recess is recessed from the DBR layer surface and is arranged inside the first opening when viewed in the thickness direction.

4. The surface emitting laser element of claim 3, wherein the first recess reaches the first DBR layer.

5. The surface emitting laser element of claim 3, wherein the first recess comprises a recess side surface having at least a portion configured by the second DBR layer, and

wherein the surface conductive layer includes a side surface portion formed over the recess side surface.

6. The surface emitting laser element of claim 5, wherein the side surface portion and the first opening extend in the same direction when viewed in the thickness direction.

7. The surface emitting laser element of claim 1, wherein the first opening has a closed annular shape or a partially opened annular shape.

8. The surface emitting laser element of claim 5, wherein the surface conductive layer comprises a second surface portion that defines a portion of the first opening and the second surface portion is separated from a first surface portion with the first opening interposed therebetween when viewed in the thickness direction, and

wherein the second surface portion is electrically connected to the side surface portion.

9. The surface emitting laser element of claim 8, wherein the second surface portion and the first opening extend in the same direction when viewed in the thickness direction.

10. The surface emitting laser element of claim 8, wherein the surface conductive layer comprises:

a connecting portion located between the first surface portion and the second surface portion and electrically connected to the first surface portion and the second surface portion; and

a second contact portion located between the second surface portion and the second DBR layer and electrically connected to the second surface portion and the second DBR layer.

11. The surface emitting laser element of claim 1, further comprising a current confinement layer located in the second DBR layer,

wherein the current confinement layer comprises an opening overlapping with the first opening of the surface conductive layer when viewed in the thickness direction, and

wherein the opening of the current confinement layer and the first opening of the surface conductive layer extend in the same direction when viewed in the thickness direction.

12. The surface emitting laser element of claim 1, further comprising a semiconductor substrate and a rear conductive layer,

wherein the first DBR layer is located between the semiconductor substrate and the second DBR layer, and the semiconductor substrate is located between the first DBR layer and the rear conductive layer,

wherein the surface conductive layer comprises a wire bonding pad, and a second recess is formed in the surface conductive layer to be recessed from a DBR layer surface, and

wherein the second recess is located between the wire bonding pad and the first opening when viewed in the thickness direction.

13. An optical device, comprising:

the surface emitting laser element of claim 1;

a mounting board on which the surface emitting laser element is arranged; and

a wire bonded to the surface emitting laser element and the mounting board.

14. A surface emitting laser element, comprising:

a first distribution Bragg reflector (DBR) layer having a first conductivity type;

a second DBR layer having a second conductivity type opposite to the first conductivity type;

an active layer located between the first DBR layer and the second DBR layer;

an insulating layer formed over the second DBR layer; and

a surface conductive layer formed over the insulating layer,

wherein a first opening, which exposes the insulating layer and overlaps with the active layer when viewed in a thickness direction of the first DBR layer, is formed in the surface conductive layer, and the first opening extends and has an annular shape when viewed in the thickness direction,

wherein the second DBR layer comprises a DBR layer surface that is located on an opposite side from where the first DBR layer is located,

wherein a first recess is recessed from the DBR layer surface and is arranged inside the first opening when viewed in the thickness direction,

wherein a second opening, which exposes the insulating layer and overlaps with the active layer when viewed in the thickness direction, is formed in the surface conductive layer, and

wherein the second opening is located inside the first recess when viewed in the thickness direction.

15. The surface emitting laser element of claim 14, wherein the second opening has an annular shape when viewed in the thickness direction.

16. A surface emitting laser element, comprising:

a substrate having a first surface that faces a first direction;

a first distribution Bragg reflector (DBR) layer having a first conductivity type and formed over the first surface;

an active layer formed over the first DBR layer;

a second DBR layer having a second conductivity type, which is opposite to the first conductivity type, and formed over the active layer;

an insulating layer formed over the second DBR layer and in contact with a portion of the first DBR layer, the active layer and the second DBR layer; and

a conductive layer formed over the insulating layer and in contact with a portion of the second DBR layer, a portion of the insulating layer being exposed via the conductive layer,

wherein a first opening, which exposes the insulating layer and overlaps with the active layer when viewed in the first direction of the first DBR layer, is formed in the conductive layer, and the first opening extends and has an annular shape when viewed in the first direction,

wherein the conductive layer comprises a bonding pad,

wherein the conductive layer comprises a first recess located between the first opening and the bonding pad, and

wherein an additional opening, which exposes the insulating layer and overlaps with the active layer when viewed in the first direction of the first DBR layer, is formed in the conductive layer, and the additional opening has an annular shape and is connected to the first opening.

17. The surface emitting laser element of claim 16, wherein the second DBR layer comprises a DBR layer surface that is located on an opposite side from where the first DBR layer is located, and

wherein an additional recess is recessed from the DBR layer surface and is arranged inside the first opening when viewed in the first direction.