# US 2008/0187015 A1 · VCSEL, manufacturing method thereof, optical device, light irradiation device, data processing device, light sending device, optical spatial transmission device, and optical transmission system

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- Number: US 2008/0187015 A1
- Document ID: US20080187015A1
- Status: Published application
- Kind: A1
- Application number: 11/880,494
- Filed: 2007-07-23
- Published: 2008-08-07
- Earliest claimed: 2007-02-02
- Assignees: Fuji Xerox Co., Ltd.
- Inventors: Masahiro Yoshikawa; Masateru Yamamoto; Takashi Kondo
- Web page: https://patentgrep.com/patent/US20080187015A1

## CPC

- H01S 5/18333: {only above the active layer}
- B82Y 20/00: Nanooptics, e.g. quantum optics or photonic crystals
- H01S 5/18394: {Apertures, e.g. defined by the shape of the upper electrode}
- H01S 5/02251: using optical fibres
- H01S 5/02253: using lenses
- H01S 5/04252: {characterised by the material}
- H01S 5/04254: {characterised by the shape}
- H01S 5/18311: {using selective oxidation}
- H01S 5/18358: {containing spacer layers to adjust the phase of the light wave in the cavity}
- H01S 5/3432: {the whole junction comprising only (AI)GaAs}
- H01S 2301/18: Semiconductor lasers with special structural design for influencing the near- or far-field
- H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES

## Abstract

A VCSEL includes a first conductivity-type first semiconductor mirror layer on a substrate, an active region thereon, a second conductivity-type second semiconductor mirror layer thereon, and a current confining layer in proximity to the active region. A mesa structure is formed such that at least a side surface of the current confining layer is exposed. The current confining layer includes a first semiconductor layer having an Al-composition and a second semiconductor layer having an Al-composition and being formed nearer to the active region than the first semiconductor layer does. Al concentration of the first semiconductor layer is higher than that of the second semiconductor layer. When oscillation wavelength of laser light is λ, optical thickness being sum of the thickness of the first and second semiconductor layers is λ/4. The first and second semiconductor layers are selectively oxidized from the side surface of the mesa structure.

## Claims

### Claim 1

A Vertical-Cavity Surface-Emitting Laser diode (VCSEL) comprising:
a first semiconductor mirror layer of a first conductivity type on a substrate, an active region on the first semiconductor mirror layer, a second semiconductor mirror layer of a second conductivity type on the active region, and a current confining layer in proximity to the active region; and
a mesa structure formed such that at least a side surface of the current confining layer is exposed; and
the current confining layer comprising a first semiconductor layer including an Al-composition and a second semiconductor layer including an Al-composition and being formed nearer to the active region than the first semiconductor layer does, and Al concentration of the first semiconductor layer being higher than Al concentration of the second semiconductor layer, and optical thickness that is sum of the thickness of the first and second semiconductor layers being λ/4 when oscillation wavelength of laser light is λ, and the first and second semiconductor layers being selectively oxidized from the side surface of the mesa structure.

### Claim 2 (depends on 1)

The VCSEL according to claim 1, wherein the second semiconductor layer in the current confining layer is formed adjacent to the active region, and the first semiconductor layer is formed adjacent to the second semiconductor layer.

### Claim 3 (depends on 1)

The VCSEL according to claim 1, wherein the current confining layer is formed in the second semiconductor mirror layer, and the first semiconductor layer is an AlxGa1-xAs layer of the second conductivity type, and the second semiconductor layer is an AlyGa1-yAs layer of the second conductivity type, and x>y.

### Claim 4 (depends on 1)

The VCSEL according to claim 1, wherein the current confining layer is formed in the first semiconductor mirror layer, and the first semiconductor layer is an AlxGa1-xAs layer of the first conductivity type, and the second semiconductor layer is an AlyGa1-yAs layer of the first conductivity type, and x>y.

### Claim 5 (depends on 3)

The VCSEL according to claim 3, wherein x of the first semiconductor layer equals to 1, and y of the second semiconductor layer is about 0.85<y<0.90.

### Claim 6 (depends on 3)

The VCSEL according to claim 3, wherein the second semiconductor mirror layer is formed by alternately stacking a first AlGaAs layer having a high Al-composition and a second AlGaAs layer having a low Al-composition, and Al concentration of the second semiconductor layer in the current confining layer is lower than Al concentration of the first AlGaAs layer.

### Claim 7 (depends on 4)

The VCSEL according to claim 4, wherein the first semiconductor mirror layer is formed by alternately stacking a first AlGaAs layer having a high Al-composition and a second AlGaAs layer having a low Al-composition, and Al concentration of the second semiconductor layer in the current confining layer is lower than Al concentration of the first AlGaAs layer.

### Claim 8 (depends on 1)

The VCSEL according to claim 1, wherein the diameter of a conductive region surrounded by an oxidized region formed in the first semiconductor layer in the current confining layer is at least equal to or smaller than 5.0 micrometers.

### Claim 9 (depends on 1)

The VCSEL according to claim 1, wherein the second semiconductor mirror layer comprises a contact layer in the uppermost layer, and an electrode layer on which an opening for emitting laser light being formed is formed on the contact layer.

### Claim 10

A method for manufacturing a Vertical-Cavity Surface-Emitting Laser diode (VCSEL) comprising:
forming a first semiconductor mirror layer of a first conductivity type on a substrate, an active region on the first semiconductor mirror layer, a second semiconductor mirror layer of a second conductivity type on the active region, and a current confining layer in proximity to the active region such that the current confining layer comprises a first semiconductor layer including an Al-composition and a second semiconductor layer including an Al-composition and being formed nearer to the active region than the first semiconductor layer does, and Al concentration of the first semiconductor layer is higher than Al concentration of the second semiconductor layer, and optical thickness that is the sum of the thickness of the first and second semiconductor layers becomes λ/4 when oscillation wavelength of laser light is λ;
forming a mesa structure such that at least a side surface of the current confining layer is exposed; and
concurrently and selectively oxidizing the first and second semiconductor layers in the current confining layer from the side surface of the mesa structure.

### Claim 11 (depends on 10)

The fabrication method according to claim 10, wherein the second semiconductor layer in the current confining layer is formed adjacent to the active region, and the first semiconductor layer is formed adjacent to the second semiconductor layer.

### Claim 12 (depends on 10)

The fabrication method according to claim 10, wherein the current confining layer is formed in the second semiconductor mirror layer, and the first semiconductor layer is an AlxGa1-xAs layer of the second conductivity type, and the second semiconductor layer is an AlyGa1-yAs layer of the second conductivity type, and x>y.

### Claim 13 (depends on 10)

The fabrication method according to claim 10, wherein the current confining layer is formed in the first semiconductor mirror layer, and the first semiconductor layer is an AlxGa1-xAs layer of the first conductivity type, and the second semiconductor layer is an AlyGa1-yAs layer of the first conductivity type, and x>y.

### Claim 14 (depends on 12)

The fabrication method according to claim 12, wherein x of the first semiconductor layer equals to 1, and y of the second semiconductor layer is about 0.85<y<0.90.

### Claim 15 (depends on 10)

The fabrication method according to claim 10, wherein the fabrication method further comprising: forming an electrode layer, on which an opening for emitting laser light being formed, on the second semiconductor mirror layer.

### Claim 16

An optical device comprising:
a VCSEL;
an electrical connecting terminal electrically coupled to the VCSEL; and
an optical component for injecting light that is emitted from the VCSEL,
the VCSEL including a first semiconductor mirror layer of a first conductivity type on a substrate, an active region on the first semiconductor mirror layer, a second semiconductor mirror layer of a second conductivity type on the active region, and a current confining layer in proximity to the active region, and a mesa structure formed such that at least a side surface of the current confining layer is exposed, and the current confining layer comprising a first semiconductor layer including an Al-composition and a second semiconductor layer including an Al-composition and being formed nearer to the active region than the first semiconductor layer does, and Al concentration of the first semiconductor layer being higher than Al concentration of the second semiconductor layer, and optical thickness that is sum of the thickness of the first and second semiconductor layers being λ/4 when oscillation wavelength of laser light is λ, and the first and second semiconductor layers being selectively oxidized from the side surface of the mesa structure.

### Claim 17

A light irradiation device comprising:
a VCSEL;
an optical component comprising at least one of a lens or a mirror; and
an irradiation unit for irradiating light that is emitted from the VCSEL through the optical component,
the VCSEL including a first semiconductor mirror layer of a first conductivity type on a substrate, an active region on the first semiconductor mirror layer, a second semiconductor mirror layer of a second conductivity type on the active region, and a current confining layer in proximity to the active region, and a mesa structure formed such that at least a side surface of the current confining layer is exposed, and the current confining layer comprising a first semiconductor layer including an Al-composition and a second semiconductor layer including an Al-composition and being formed nearer to the active region than the first semiconductor layer does, and Al concentration of the first semiconductor layer being higher than Al concentration of the second semiconductor layer, and optical thickness that is sum of the thickness of the first and second semiconductor layers being λ/4 when oscillation wavelength of laser light is λ, and the first and second semiconductor layers being selectively oxidized from the side surface of the mesa structure.

### Claim 18

A data processing device comprising:
an optical device; and
a sending unit for sending light that is emitted from the VCSEL,
the optical device including the VCSEL, an electrical connecting terminal electrically coupled to the VCSEL, and an optical component for injecting light that is emitted from the VCSEL,
the VCSEL including a first semiconductor mirror layer of a first conductivity type on a substrate, an active region on the first semiconductor mirror layer, a second semiconductor mirror layer of a second conductivity type on the active region, and a current confining layer in proximity to the active region, and a mesa structure formed such that at least a side surface of the current confining layer is exposed, and the current confining layer comprising a first semiconductor layer including an Al-composition and a second semiconductor layer including an Al-composition and being formed nearer to the active region than the first semiconductor layer does, and Al concentration of the first semiconductor layer being higher than Al concentration of the second semiconductor layer, and optical thickness that is sum of the thickness of the first and second semiconductor layers being λ/4 when oscillation wavelength of laser light is λ, and the first and second semiconductor layers being selectively oxidized from the side surface of the mesa structure.

### Claim 19

A light sending device comprising:
an optical device; and
a sending unit for sending light that is emitted from a VCSEL,
the optical device including the VCSEL, an electrical connecting terminal electrically coupled to the VCSEL, and an optical component for injecting light that is emitted from the VCSEL,
the VCSEL including a first semiconductor mirror layer of a first conductivity type on a substrate, an active region on the first semiconductor mirror layer, a second semiconductor mirror layer of a second conductivity type on the active region, and a current confining layer in proximity to the active region, and a mesa structure formed such that at least a side surface of the current confining layer is exposed, and the current confining layer comprising a first semiconductor layer including an Al-composition and a second semiconductor layer including an Al-composition and being formed nearer to the active region than the first semiconductor layer does, and Al concentration of the first semiconductor layer being higher than Al concentration of the second semiconductor layer, and optical thickness that is sum of the thickness of the first and second semiconductor layers being λ/4 when oscillation wavelength of laser light is λ, and the first and second semiconductor layers being selectively oxidized from the side surface of the mesa structure.

### Claim 20

An optical spatial transmission device comprising:
an optical device; and
a transmission unit for spatially transmitting light that is emitted from a VCSEL,
the optical device including the VCSEL, an electrical connecting terminal electrically coupled to the VCSEL, and an optical component for injecting light that is emitted from the VCSEL,
the VCSEL including a first semiconductor mirror layer of a first conductivity type on a substrate, an active region on the first semiconductor mirror layer, a second semiconductor mirror layer of a second conductivity type on the active region, and a current confining layer in proximity to the active region, and a mesa structure formed such that at least a side surface of the current confining layer is exposed, and the current confining layer comprising a first semiconductor layer including an Al-composition and a second semiconductor layer including an Al-composition and being formed nearer to the active region than the first semiconductor layer does, and Al concentration of the first semiconductor layer being higher than Al concentration of the second semiconductor layer, and optical thickness that is sum of the thickness of the first and second semiconductor layers being λ/4 when oscillation wavelength of laser light is λ, and the first and second semiconductor layers being selectively oxidized from the side surface of the mesa structure.

### Claim 21

An optical transmission system comprising:
an optical device; and
a transmission unit for transmitting light that is emitted from a VCSEL,
the optical device including the VCSEL, an electrical connecting terminal electrically coupled to the VCSEL, and an optical component for injecting light that is emitted from the VCSEL,
the VCSEL including a first semiconductor mirror layer of a first conductivity type on a substrate, an active region on the first semiconductor mirror layer, a second semiconductor mirror layer of a second conductivity type on the active region, and a current confining layer in proximity to the active region, and a mesa structure formed such that at least a side surface of the current confining layer is exposed, and the current confining layer comprising a first semiconductor layer including an Al-composition and a second semiconductor layer including an Al-composition and being formed nearer to the active region than the first semiconductor layer does, and Al concentration of the first semiconductor layer being higher than Al concentration of the second semiconductor layer, and optical thickness that is sum of the thickness of the first and second semiconductor layers being λ/4 when oscillation wavelength of laser light is λ, and the first and second semiconductor layers being selectively oxidized from the side surface of the mesa structure.