Quantum-cascade laser element and quantum-cascade laser device

Patent metadata

Field	Value
Publication number	US-2023139139-A1
Application number	US-202117914806-A
Country	US
Kind code	A1
Filing date	Mar 25, 2021
Priority date	Apr 2, 2020
Publication date	May 4, 2023
Grant date	—

Abstract

A quantum-cascade laser element includes: an embedding layer including a first portion formed on a side surface of a ridge portion, and a second portion extending from an edge portion of the first portion on a side of a semiconductor substrate along a width direction of the semiconductor substrate; and a metal layer formed at least on a top surface of the ridge portion and on the first portion. A surface of the second portion on a side opposite to the semiconductor substrate is located between a surface of an active layer on a side opposite to the semiconductor substrate and a surface of the active layer on a side of the semiconductor substrate. When viewed in the width direction of the semiconductor substrate, a part of the metal layer on the first portion overlaps the active layer. The metal layer is directly formed on the first portion.

First claim

1 : A quantum-cascade laser element comprising:
a semiconductor substrate; a semiconductor laminate formed on the semiconductor substrate to include a ridge portion configured to include an active layer having a quantum-cascade structure; an embedding layer including a first portion formed on a side surface of the ridge portion, and a second portion extending from an edge portion of the first portion on a side of the semiconductor substrate along a width direction of the semiconductor substrate; and a metal layer formed at least on a top surface of the ridge portion and on the first portion, wherein, in a thickness direction of the semiconductor substrate, a surface of the second portion on a side opposite to the semiconductor substrate is located between a surface of the active layer on a side opposite to the semiconductor substrate and a surface of the active layer on a side of the semiconductor substrate, when viewed in the width direction of the semiconductor substrate, a part of the metal layer on the first portion overlaps the active layer, and the metal layer is directly formed on the first portion.

2 : The quantum-cascade laser element according to claim 1 ,
wherein a thickness of the first portion is thinner than a thickness of the second portion.

3 : The quantum-cascade laser element according to claim 1 ,
wherein the metal layer is formed on the top surface of the ridge portion, on the first portion, and on the second portion, and a dielectric layer is disposed between the second portion and the metal layer.

4 : The quantum-cascade laser element according to claim 3 ,
wherein the dielectric layer is formed such that a part of the second portion is exposed from the dielectric layer, and the metal layer is in contact with the second portion at the part.

5 : The quantum-cascade laser element according to claim 3 ,
wherein an opening that exposes an inner portion of the second portion from the dielectric layer is formed in the dielectric layer, the inner portion being continuous with the first portion, and the metal layer is in contact with the inner portion through the opening.

6 : The quantum-cascade laser element according to claim 5 ,
wherein a width of the opening in the width direction of the semiconductor substrate is more than or equal to two times a width of the active layer.

7 : The quantum-cascade laser element according to claim 5 ,
wherein a width of the opening in the width direction of the semiconductor substrate is more than or equal to ten times a thickness of the second portion.

8 : The quantum-cascade laser element according to claim 3 , further comprising:
a wire made of metal, that is electrically connected to the metal layer, and a connection position between the metal layer and the wire overlaps the dielectric layer when viewed in the thickness direction of the semiconductor substrate.

9 : A quantum-cascade laser device comprising:
the quantum-cascade laser element according to claim 1 ; and a drive unit that drives the quantum-cascade laser element.

Assignees

• Hamamatsu Photonics Kk

Inventors

• Sugiyama Atsushi
• Furuta Shinichi
• Fujita Kazuue

Classifications

• 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

• H01S5/04254

  characterised by the shape · CPC title

• H01S5/2224

  semi-insulating semiconductors · CPC title

• H01S5/0654

  Single longitudinal mode emission · CPC title

• H01S5/2275

  mesa created by etching · CPC title