Optoelectronic device comprising a semiconductor layer based on GeSn having a single-crystal portion with a direct band structure and an underlying barrier region

Patent metadata

Field	Value
Publication number	US-12040595-B2
Application number	US-202218057492-A
Country	US
Kind code	B2
Filing date	Nov 21, 2022
Priority date	Nov 23, 2021
Publication date	Jul 16, 2024
Grant date	Jul 16, 2024

Abstract

An optoelectronic device including a crystalline semiconductor layer based on GeSn and including a pin junction. This formed semiconductor layer includes a base portion; a single-crystal intermediate portion having an average value x pi1 of proportion of tin less than x ps1 , thus forming a barrier region against charge carriers flowing in an upper portion; and the single-crystal upper portion including a homogeneous medium with a proportion of tin x ps1 , and vertical structures having an average value x ps2 of proportion of tin greater than x ps1 , thus forming regions for emitting or for receiving infrared radiation.

First claim

The invention claimed is:

1. An optoelectronic device for emitting or for receiving an infrared radiation, comprising:
a nucleation layer;
a crystalline semiconductor layer comprising GeSn, extending in a main plane, having an upper face opposite to the nucleation layer, and comprising:
a base portion, extending over and in contact with the nucleation layer;
an upper portion, extending over the base portion, a single-crystal, and under a tensile stress with an average value Cps in the main plane of the crystalline semiconductor layer, composed of a homogeneous medium having a uniform value x ps1 of an atomic proportion of tin of the homogeneous medium, the average value ε ps of the tensile stresses and the uniform value x ps1 of the atomic proportion of tin being such that the upper portion has a direct bandgap structure;
a pin semiconductor junction, comprising a doped region of an n type and a doped region of a p type, flush with the upper face, and an intrinsic region situated within the upper portion and extending between the doped regions; and
metal polarizing contacts, situated on and in contact with the doped regions,
wherein the single-crystal of the upper portion comprises, aside from the homogeneous medium, vertical structures extending in the homogeneous medium along an axis orthogonal to the main plane over a whole thickness of the upper portion, and having an average value x ps2 of the atomic proportion of tin greater than the uniform value x ps1 , thus forming regions for emitting or for receiving said infrared radiation, and
wherein the crystalline semiconductor layer furthermore comprises an intermediate portion, situated between and in contact with the base portion and the upper portion along an axis orthogonal to the main plane, the single-crystal of the upper portion, and a region extending in the main plane over its whole width and having an average value x pi1 of the atomic proportion of tin less than the uniform value x ps1 , thus forming a barrier region against charge carriers flowing in the upper portion.

2. The optoelectronic device according to claim 1 , wherein the base portion has an average value x pb greater than the average value x pi1 of the atomic proportion of tin in the intermediate portion and less than the average value x ps2 of the atomic proportion of tin in the vertical structures.

3. The optoelectronic device according to claim 2 , wherein the average value x pb of the atomic proportion of tin in the base portion is in the range between 4% and 10%.

4. The optoelectronic device according to claim 1 , wherein the base portion extends up to a surface of the upper face, and surrounds the intermediate portion and the upper portion in the main plane, at least one of the doped regions being situated within the base portion.

5. The optoelectronic device according to claim 1 , wherein the intermediate portion entirely covers the base portion, the doped regions being situated within the upper portion.

6. The optoelectronic device according to claim 1 , wherein the semiconductor layer is formed, starting from the nucleation layer, of a lower region and a single-crystal upper region which covers the lower region, the upper portion being situated within the upper region.

7. The optoelectronic device according to claim 1 , wherein the nucleation layer is made of germanium and lies on a carrier substrate preferably comprising silicon.

8. The optoelectronic device according to claim 1 , forming a laser diode or a light-emitting diode designed to generate infrared radiation, or a photodiode designed to detect infrared radiation.

9. The optoelectronic device according to claim 1 , forming a laser diode, comprising a lower waveguide formed within the nucleation layer of germanium, an active waveguide coupled to the lower waveguide, comprising the gain medium and formed within the semiconductor layer, and at least one Bragg reflector situated within the lower waveguide or within the active waveguide.

Assignees

• Commissariat Energie Atomique

Inventors

• Casiez Lara
• Reboud Vincent
• Acosta Alba Pablo

Classifications

• H10F77/1665

  including Group IV-IV materials, e.g. SiGe or SiC · CPC title

• H10F71/1035

  having multiple Group IV elements, e.g. SiGe or SiC · CPC title

• H10H20/014

  having light-emitting regions comprising only Group IV materials · CPC title

• H10F30/2235 Primary

  the devices comprising Group IV amorphous materials · CPC title

• H01S5/3428

  layer orientation perpendicular to the substrate · CPC title