Fabrication method of semiconductor luminescent device

Abstract

A fabrication method of a semiconductor luminescent device includes forming a compound semiconductor layer having a structure in which a first conductivity-type clad layer, an active layer, a second conductivity-type clad layer are layered in order on a substrate, the second conductivity-type being different from the first conductivity-type and forming a low-refractive-index region in a waveguide in an area to be an end face from which an output light from the waveguide in the compound semiconductor layer is emitted, the low-refractive-index region having an equivalent refractive-index lower than that of another area in the waveguide. The step of forming the low-refractive-index region includes determining a width of the low-refractive-index region in a longitudinal direction of the waveguide so that an emission angle of the output light of the semiconductor luminescent device is controlled to be a desirable value, and forming the low-refractive-index region having the width.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will be described in detail with reference to the following drawings, wherein:

FIG. 1 illustrates an emission angle of a semiconductor laser;

FIG. 2 illustrates a perspective view of a semiconductor laser fabricated through a method in accordance with a first embodiment;

FIG. 3A illustrates a cross sectional view taken along a line A-A of FIG. 2;

FIG. 3B illustrates a cross sectional view taken along a line B-B of FIG. 2;

FIG. 4A illustrates a result in a case where a horizontal emission angle θ_H and a vertical emission angle θ_V with respect to a low-refractive-index region is measured;

FIG. 4B illustrates a result in a case where a horizontal emission angle θ_H and a vertical emission angle θ_V with respect to a low-refractive-index region is calculated;

FIG. 5A through FIG. 5C illustrate a cross sectional view showing a fabrication method of a semiconductor laser in accordance with a first embodiment;

FIG. 6A through FIG. 6C illustrate a cross sectional view showing a fabrication method of a semiconductor laser in accordance with a first embodiment;

FIG. 7A through FIG. 7C illustrate a cross sectional view showing a fabrication method of a semiconductor laser in accordance with a first embodiment;

FIG. 8A and FIG. 8B illustrate a fabrication method of a semiconductor laser in accordance with a second embodiment;

FIG. 9 illustrates a flow chart showing a fabrication method of a semiconductor laser in accordance with a second embodiment;

FIG. 10 illustrates a cross sectional view showing a fabrication method of a semiconductor laser in accordance with a third embodiment;

FIG. 11A through FIG. 11C illustrate a cross sectional view showing a fabrication method of a semiconductor laser in accordance with a fourth embodiment;

FIG. 12 illustrates a top view showing a fabrication method of a semiconductor laser in accordance with a fourth embodiment;

FIG. 13 illustrates a perspective view of a semiconductor laser fabricated through a method in accordance with a fourth embodiment; and

FIG. 14 illustrates a cross sectional view taken along a line B-B of FIG. 13.

Claims

1. A fabrication method of a semiconductor luminescent device comprising: forming a compound semiconductor layer having a structure in which a first conductivity-type clad layer, an active layer, a second conductivity-type clad layer are layered in order on a substrate,the second conductivity-type being different from the first conductivity-type; andforming a low-refractive-index region in a waveguide in an area to be an end face from which an output light from the waveguide in the compound semiconductor layer is emitted,the low-refractive-index region having an equivalent refractive-index lower than that of another area in the waveguide,wherein the step of forming the low-refractive-index region comprises:determining a width of the low-refractive-index region in a longitudinal direction of the waveguide so that an emission angle of the output light of the semiconductor luminescent device is controlled to be a desirable value; andforming the low-refractive-index region having the width.

2. A fabrication method of a semiconductor luminescent device comprising: forming a compound semiconductor layer having a structure in which a first conductivity-type clad layer, an active layer, a second conductivity-type clad layer are layered in order on a substrate,the second conductivity-type being different from the first conductivity-type; andforming a low-refractive-index region in a waveguide in an area to be an end face from which an output light from the waveguide in the compound semiconductor layer is emitted,the low-refractive-index region having an equivalent refractive-index lower than that of another area in the waveguide,wherein the step of forming the low-refractive-index region comprises forming the low-refractive-index regions in the semiconductor luminescent devices in a wafer so as to have a width in a longitudinal direction of the waveguide,the widths being different from each other.

3. A fabrication method of a semiconductor luminescent device comprising: forming a compound semiconductor layer having a structure in which a first conductivity-type clad layer, an active layer, a second conductivity-type clad layer are layered in order on a substrate,the second conductivity-type being different from the first conductivity-type; andforming a low-refractive-index region in a waveguide in an area to be an end face from which an output light from the waveguide in the compound semiconductor layer is emitted,the low-refractive-index region having an equivalent refractive-index lower than that of another area in the waveguide;wherein the step of forming the low-refractive-index region comprises:determining a width of the low-refractive-index region in a longitudinal direction of the waveguide according to an emission angle of the output light of a semiconductor luminescent device fabricated in advance; andforming the low-refractive-index region having the width.

4. The method as claimed in claim 1, wherein the width of the low-refractive-index region in the longitudinal direction of the waveguide is controlled with a selection of a photo mask in the step of controlling the emission angle to be the desirable value.

5. The method as claimed in claim 2, wherein the step of forming the low-refractive-index region comprises forming the low-refractive-index regions so that the widths of the low-refractive-index regions in the longitudinal direction of the waveguide are different from each other, with use of photo masks of which size is different from each other.

6. The method as claimed in any of claims 1 to 3, wherein the step of forming the low-refractive-index region comprises: forming a layer including zinc oxide and silicon oxide so as to contact to a region to be the low-refractive-index region; anddiffusing zinc of the zinc oxide into the compound semiconductor layer in the region to be the low-refractive-index region.

7. The method as claimed in any of claims 1 to 3, wherein the step of forming the low-refractive-index region comprises implanting an ion of an impurity into a region to be the low-refractive-index region.

8. The method as claimed in any of claims 1 to 3, wherein the step of forming the low-refractive-index region comprises forming the compound semiconductor layer so that at least a part of the compound semiconductor layer in the low-refractive-index region has a thickness lower than that of another area of the waveguide in the step of forming the compound semiconductor layer.

9. The method as claimed in any of claims 1 to 3, wherein the substrate is an off-substrate having a surface of which crystal face is oblique toward [1 1 1] direction or toward [1 −1 −1] direction from (1 0 0) face.