Method for producing quantum cascade laser and quantum cascade laser

Patent metadata

Field	Value
Publication number	US-2017170634-A1
Application number	US-201615372346-A
Country	US
Kind code	A1
Filing date	Dec 7, 2016
Priority date	Dec 10, 2015
Publication date	Jun 15, 2017
Grant date	—

Abstract

A method for producing a quantum cascade laser includes the steps of growing a stacked semiconductor layer including a core layer; forming an insulating mask on the stacked semiconductor layer; forming a mesa structure including the core layer by etching the stacked semiconductor layer through the insulating mask; growing a buried layer on a side surface of the mesa structure using the insulating mask by supplying a halogen-based substance and a gas containing a raw material, the buried layer having a thickness larger than a height of the mesa structure; producing a substrate product including the mesa structure and a buried region by processing of the buried layer using a chemical-mechanical polishing method; and after removal of the insulating mask, producing a distributed reflection structure by etching the mesa structure and the buried region of the substrate product using a mask.

First claim

What is claimed is:

1 . A method for producing a quantum cascade laser, comprising the steps of:
growing a stacked semiconductor layer on a principal surface of a substrate, the stacked semiconductor layer including a core layer; forming an insulating mask on the stacked semiconductor layer; forming a mesa structure including the core layer on the principal surface of the substrate by etching the stacked semiconductor layer through the insulating mask; growing a buried layer on a side surface of the mesa structure using the insulating mask as a selective mask by supplying a halogen-based substance and a gas containing a raw material into a growth chamber, the buried layer having a thickness larger than a height of the mesa structure; producing a substrate product including the mesa structure and a buried region by processing of the buried layer using a chemical-mechanical polishing method; after removal of the insulating mask, forming a mask on the mesa structure and the buried region of the substrate product; and producing a distributed reflection structure by etching the mesa structure and the buried region of the substrate product using the mask.

2 . The method according to claim 1 , wherein, in the step of producing the substrate product, the processing of the buried layer includes a step of detecting an endpoint of the processing using the insulating mask.

3 . The method according to claim 1 ,
wherein the buried layer is made of InP, and the buried layer has a ( 100 ) plane that is exposed at an upper surface of the buried layer.

4 . The method according to claim 1 ,
wherein the mesa structure has an upper layer extending along a first reference plane, the buried layer includes a side surface extending along a second reference plane inclined with respect to the first reference plane, and the side surface of the buried layer includes a ( 111 )B plane.

5 . The method according to claim 1 , wherein, in the step of producing the substrate product, the processing of the buried layer is performed by using a polishing liquid that contains a Br/methanol mixture.

6 . A quantum cascade laser, comprising:
a substrate having a principal surface including a first area, a second area, and a third area, the first area being disposed between the second area and the third area; a waveguide structure provided on the first area of the substrate, the waveguide structure including a core layer, the waveguide structure extending in a direction of a first axis; a buried region provided on the second area and the third area of the substrate, the waveguide structure being embedded by the buried region; and a distributed reflection structure optically coupled to an end facet of the waveguide structure, the distributed reflection structure having a larger width than the waveguide structure, the distributed reflection structure including one or more semiconductor walls extending in a direction of a second axis that intersects the first axis, wherein each of the semiconductor walls includes a first portion provided on the first area, a second portion provided on the second area, and a third portion provided on the third area, the second portion, the first portion, and the third portion are arranged in that order in the direction of the second axis, and each of the second portion and the third portion has an upper surface higher than an upper surface of the first portion.

Assignees

• Sumitomo Electric Industries

Inventors

• Tsuji Yukihiro

Classifications

• H01S5/2275

  mesa created by etching · CPC title

• H01S5/3402 Primary

  intersubband lasers, e.g. transitions within the conduction or valence bands · CPC title

• H01S5/12

  the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers (comprising a photonic bandgap structure H01S5/11; surface-emitting lasers H01S5/18) · CPC title

• H01S5/2224

  semi-insulating semiconductors · CPC title

• H01S5/3401 Primary

  having no PN junction, e.g. unipolar lasers, intersubband lasers, quantum cascade lasers · CPC title