Method for manufacturing optical device and optical device

Patent metadata

Field	Value
Publication number	US-2021210924-A1
Application number	US-202117141223-A
Country	US
Kind code	A1
Filing date	Jan 5, 2021
Priority date	Jan 8, 2020
Publication date	Jul 8, 2021
Grant date	—

Abstract

An object of the present invention is to provide a method for manufacturing an optical device having a laser diode, which method is suitable for mass production, and an optical device having a laser diode which allows accurate property evaluations thereof with small measurement errors. Specifically, the method includes: an etching process of etching a semiconductor lamination unit to form a mesa structure having a resonator end face, thereby forming a laser diode; and a reflecting layer forming process of forming a light reflecting layer such that the light reflecting layer covers entire side surfaces of the mesa structure, wherein the semiconductor lamination unit has a substate, a n-type clad layer including a nitride semiconductor layer having n-type conductivity, a light-emitting layer including at least one quantum well, and a p-type clad layer including a nitride semiconductor layer having p-type conductivity, laminated in this order.

First claim

1 . A method for manufacturing an optical device, wherein the method comprises:
an etching process of etching a semiconductor lamination unit to form a mesa structure having a resonator end face, thereby forming a laser diode; and a reflecting layer forming process of forming a light reflecting layer such that the light reflecting layer covers entire side surfaces of the mesa structure, wherein the semiconductor lamination unit has a n-type clad layer formed on a substrate and including a nitride semiconductor layer having n-type conductivity, a light-emitting layer formed on the n-type clad layer and including at least one quantum well, and a p-type clad layer formed on the light-emitting layer and including a nitride semiconductor layer having p-type conductivity.

2 . The method for manufacturing an optical device of claim 1 , further comprising a photodetector forming process of forming a photodetector having a mesa structure and capable of receiving and detecting light emitted from the resonator end face,
wherein the light reflecting layer is formed on entire side surfaces of the mesa structure of the photodetector, as well, in the reflecting layer forming process.

3 . The method for manufacturing an optical device of claim 2 , wherein the etching process includes the photodetector forming process.

4 . The method for manufacturing an optical device of claim 2 , wherein the laser diode and the photodetector are formed adjacent to each other.

5 . The method for manufacturing an optical device of claim 2 , wherein the substrate has a wafer-like configuration and a plurality of the mesa structures of the laser diodes and a plurality of the mesa structures of the photodetectors are formed on the wafer-like substrate, respectively.

6 . The method for manufacturing an optical device of claim 1 , wherein the light reflecting layer is formed by atomic layer deposition.

7 . The method for manufacturing an optical device of claim 1 , wherein the etching process carries out dry etching and wet etching in this order, the substrate is an AlN substrate, and an etching solution for the wet etching contains tetramethylammonium hydroxide.

8 . The method for manufacturing an optical device of claim 1 , further comprising a dicing process after the reflecting layer forming process,
wherein the dicing process includes individualizing the laser diodes each having a mesa structure provided with a resonator end face.

9 . The method for manufacturing an optical device of claim 1 , further comprising between the etching process and the reflecting layer forming process:
an electrode portion forming process of forming a p electrode portion electrically connected with the p-type clad layer of the laser diode; and an insulating layer forming process of forming an insulating layer such that the insulating layer covers the p electrode portion.

10 . An optical device having a laser diode, wherein the laser diode comprises:
a substrate; a n-type clad layer formed on the substrate and including a nitride semiconductor layer having n-type conductivity; a light-emitting layer formed on the n-type clad layer and including at least one quantum well; and a p-type clad layer formed on the light-emitting layer and including a nitride semiconductor layer having p-type conductivity, wherein at least a portion of the n-type clad layer, the light-emitting layer and the p-type clad layer constitute a mesa structure having a resonator end face, and entire side surfaces of the mesa structure are covered with a light reflecting layer.

11 . The optical device of claim 10 , further comprising a photodetector formed on the substrate, having a mesa structure and capable of receiving and detecting light emitted from the laser diode,
wherein side surfaces of the mesa structure of the photodetector are covered with the light reflecting layer.

12 . The optical device of claim 11 , wherein a laser beam receiving face of the photodetector is positioned to be opposed to a main laser beam emitting face of the laser diode.

13 . The optical device of claim 10 , comprising a plurality of the laser diodes.

14 . The optical device of claim 10 , wherein the p-type clad layer includes: a p-type longitudinally conductive layer containing Al s Ga 1-s N (0.3≤s≤1), having film thickness smaller than 0.5 μm and a graded Al composition “s” which decreases in the direction away from the top surface of the substrate; and a p-type transversely conductive layer composed of Al t Ga 1-t N (0<t≤1).

15 . The optical device of claim 10 , wherein the light reflecting layer is a dielectric lamination film.

16 . The optical device of claim 10 , wherein the light reflecting layer is made of oxide of at least one selected from the group consisting of aluminum, hafnium, silicon, titanium, zirconium, lead, and gallium.

17 . The optical device of claim 15 , wherein the dielectric lamination film is a lamination film in which a hafnium oxide film and an aluminum oxide film are laminated at ≤1 lamination cycle.

18 . The optical device of claim 10 , wherein the substrate is an AlN substrate and an angle formed by a surface adjacent to the resonator end face, of the light reflecting layer, with respect to the (0001) plane of the AlN substrate is in the range of ≤85° and ≤95°.

19 . The optical device of claim 10 , wherein the n-type clad layer, the light-emitting layer and the p-type clad layer are AlGaN layers and the (1-100) plane of the AlGaN layers constitutes the resonator end face.

20 . The optical device of claim 10 , comprising a plurality of the laser diodes.

Assignees

• Asahi Chemical Ind
• National Univ Corporation Tokai National Higher Education And Research System

Inventors

• Zhang Ziyi
• Kushimoto Maki
• Amano Hiroshi

Classifications

• H01S5/04256

  characterised by the configuration · CPC title

• H01S5/1039

  Details on the cavity length · CPC title

• H01S5/0202

  Cleaving · CPC title

• H01S5/0264 Primary

  for monitoring the laser-output · CPC title

• H01S5/34333

  with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser · CPC title