US 7,804,875 B2 · Vertical cavity surface emitting laser module having monitoring photodiode and method of fabricating the same

Abstract

Provided are a vertical cavity surface emitting laser (VCSEL) module providing accurate alignment between a VCSEL and a monitoring photodiode (MPD) for efficiently detecting light emitted by the VCSEL and a method of fabricating the VCSEL module. The VCSEL module includes: a first mirror layer, a first semiconductor conducting layer, an active layer, a tunnel junction layer, and a second semiconductor conducting layer sequentially formed on a first region in a substrate having first and second regions; a MPD disposed on a portion of the second semiconductor conducting layer in the first region; and a VCSEL including layers having the same shapes as the first mirror layer, the first semiconductor conducting layer, the active layer, the tunnel junction layer and the second semiconductor conducting layer in the first region, and a second mirror layer formed on a portion of the second semiconductor conducting layer, and sequentially formed on the second region in the substrate. The predetermined distance is set so that light emitted by the VCSEL can be detected by the MPD.

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Drawings

Claims12

Dependent claims

A Vertical Cavity Surface Emitting Laser (VCSEL) module having a monitoring photodiode, the VCSEL module comprising:

a substrate having first and second regions spaced apart by a predetermined distance;
a monitoring photodiode disposed on a first mirror layer, a first semiconductor conducting layer, an active layer, a lower second semiconductor conducting layer, a tunnel junction layer, and directly disposed on an upper second semiconductor conducting layer in which the layers are sequentially formed on each other in the first region;
and
a VCSEL disposed on the first mirror layer, the first semiconductor conducting layer, the active layer, the lower second semiconductor conducting layer, the tunnel junction layer, and the upper second semiconductor conducting layer sequentially formed on each other in the second region of the substrate, wherein the VCSEL comprises the first mirror layer, the first semiconductor conducting layer, the active layer, the lower second semiconductor conducting layer, the tunnel junction layer, the upper second semiconductor conducting layer and a second mirror formed in the second region, wherein each of the first semiconductor conducting layer, the active layer, the lower second semiconductor conducting layer, the tunnel junction layer, and the upper second semiconductor conducting layer in the second region has a thickness which is substantially the same as the thickness of the corresponding layer in the first region;
and
a third metal layer formed to cover a portion of the upper second semiconductor conducting layer and exposing a central portion of the upper second semiconductor conducting layer in the second region,
wherein the second mirror layer formed on the exposed portion of the upper second semiconductor conducting layer and on an upper portion of the third metal layer and emitting light of the VCSEL,
wherein the second mirror layer is formed only on the upper second semiconductor conducting layer in the second region, and
wherein the predetermined distance is set so that light emitted by the VCSEL formed in the second region of the substrate can be detected by the monitoring photodiode formed in the first region of the substrate.

6 more elements

A method of fabricating a Vertical Cavity Surface Emitting Laser (VCSEL) module having a monitoring photodiode, the method comprising

sequentially forming a first mirror layer, a first semiconductor conducting layer, a lower second semiconductor conducting region, an active layer, a tunnel junction layer, and an upper second semiconductor conducting layer, an n-doped layer, an undoped layer, and a p-doped layer on a semiconductor substrate;
separating the resulting stacked structure into first and second regions to match the angle of light incident on the n-doped layer, the undoped layer, and the p-doped layer;
forming an etch stop layer over the first region and etching away the n-doped layer, the undoped layer, and the p-doped layer from the second region and away from a portion of the first region so as to form a monitoring photodiode on only a portion of the upper second semiconductor conducting layer in the first region such that the upper second semiconductor conducting layer in the second region is exposed;
forming a third metal electrode layer on a portion of the upper second semiconductor layer so as to expose a central portion of the upper second semiconductor conducting layer in the second region;
and
depositing a second mirror layer only on the portion of the upper second semiconductor conducting layer in the second region left exposed from the etching away of the n-doped layer, the undoped layer, and the p-doped layer in the second region, such that a VCSEL is formed in the second region, wherein the resulting stacked structure is separated into the first and second regions during the process of fabricating the VCSEL such that the monitoring photodiode is aligned with the VCSEL during the process of fabricating the VCSEL.

3 more elements

Dependencies are inferred from the claim text.

Description2,549 words

Summary1,042 words

#This application claims the benefit of Korean Patent Application No. 10-2005-0120082 filed on Dec. 8, 2005 and Korean Patent Application No. 10-2006-0060501 filed on Jun. 30, 2006, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein in their entirety by reference.

#1. Field of the Invention

#The present invention relates to a semiconductor laser and a method of fabricating the same, and more particularly, to a vertical cavity surface emitting laser (VCSEL) module having a monitoring photodiode (MPD) and a method of fabricating the same.

Brief description of the drawings3 figures

#The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:

#FIGS. 1A and 1B are cross-sectional views illustrating a method of fabricating a vertical cavity surface emitting laser (VCSEL) device having a monitoring photodiode (MPD) according to an embodiment of the present invention;

#FIG. 2 is a plan view illustrating a unit structure for a VCSEL device having a VCSEL monolithically integrated with a MPD according to an embodiment of the present invention; and

Detailed description1,387 words

#The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. Like reference numerals in the drawings denote like elements.

#FIGS. 1A and 1B are cross-sectional views illustrating a method of fabricating a vertical cavity surface emitting laser (VCSEL) device 100 having a monitoring photodiode (MPD) according to an embodiment of the present invention.

#Referring to FIG. 1A, a first mirror layer 12, a first semiconductor conducting layer 14, an active layer 16, a second semiconductor conducting layer 18, and a tunnel junction layer 20, and another second semiconductor conducting layer 22 are sequentially grown on a substrate 10 using a compound semiconductor epitaxial growth technique. The first and second semiconductor conducting layers 14, 18, and 22 acting as a conducting layer for injecting current may be made of a semiconductor material that dissipates heat due to its excellent thermal characteristics. The tunnel junction layer 20 defines a region into which current is injected by confining current. The active layer 16 is a gain layer that plays an essential role in laser operation. In one embodiment, the substrate 10 and the first mirror layer 12 may be formed of InP and InAlGaAs/InAlAs, respectively. The first and second semiconductor conducting layers 14, 18, and 22 may be formed of n-InP, p-InP, and n-InP, respectively. The active layer 16 may have a multi-quantum well (MQW) structure composed of InAlGaAs. In this manner, an epitaxial structure of the VCSEL device 100 is completed except for a second mirror layer 50 in FIG. 1B that will be subsequently formed.

Facts

Application

11/635,938Filed 8 Dec 2006

Priority

KR 10-2005-01200828 Dec 2005

Published

US 2007/0133642 A114 Jun 2007

Granted

28 Sep 2010

Term ends

8 Dec 2026

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification8 codes

H01S 5/02257
Out-coupling of light: using windows, e.g. specially adapted for back-reflecting light to a detector inside the housing
H01S 5/0264
Photo-diodes, e.g. transceiver devices, bidirectional devices: for monitoring the laser-output
H01S 5/0421
Electrical excitation ; Circuits therefor: characterised by the semiconducting contacting layers
H01S 5/04257
Characterised by the configuration: having positive and negative electrodes on the same side of the substrate

Timeline

8 Dec 2005Priority claimedKR 10-2005-0120082
8 Dec 2006Application filedUS 11/635,938
8 Dec 2006Assigned to Electronics and Telecommunications Research Instituteassignment of assignor's interest
14 Jun 2007PublishedUS 2007/0133642 A1
28 Sep 2010GrantedUS 7,804,875 B2
12 Oct 2026TodayWithin its term
8 Dec 2026Term endsEstimated

Vertical cavity surface emitting laser module having monitoring photodiode and method of fabricating the same

Life of this patent

Vertical cavity surface emitting laser module having monitoring photodiode and method of fabricating the same

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims12

Description2,549 words

Drawings

Classification8 codes

Life of this patent

Description2,549 words