Device for generating or detecting electromagnetic radiation, and fabrication method of the same

• US 20060214176A1
• Filed: 03/16/2006
• Published: 09/28/2006
• Est. Priority Date: 03/28/2005
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Ouchi, Toshihiko, Sekiguchi, Ryota
• Granted Patent: US 7,933,305 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G01N 21/3581 using far infrared light; using Terahertz radiation
• CPC Class Codes: H01L 31/0232 Optical elements or arrangements associated with the device H01L31/0236 takes precedence; for photovoltaic cells H01L31/054; for photovoltaic modules H02S40/20
• CPC Class Codes: H01L 31/03046 including ternary or quaternary compounds, e.g. GaAlAs, InGaAs, InGaAsP
• CPC Class Codes: H01L 31/035236 Superlattices; Multiple quantum well structures
• CPC Class Codes: H01S 1/02 solid
• CPC Class Codes: H01S 2302/02 THz - lasers, i.e. lasers with emission in the wavelength range of typically 0.1 mm to 1 mm
• CPC Class Codes: H01S 5/18305 with emission through the substrate, i.e. bottom emission
• CPC Class Codes: H01S 5/18308 having a special structure for lateral current or light confinement
• CPC Class Codes: H01S 5/18388 Lenses
• CPC Class Codes: H01S 5/2213 based on polyimide or resin
• CPC Class Codes: H01S 5/2275 mesa created by etching
• CPC Class Codes: H01S 5/3401 having no PN junction, e.g. unipolar lasers, intersubband lasers, quantum cascade lasers
• CPC Class Codes: Y02E 10/544 Solar cells from Group III-V materials

Abstract

A device for generating or detecting electromagnetic radiation includes a substrate, a gain medium provided on the substrate, a plurality of reflectors for confining electromagnetic radiation at a predetermined frequency range and substantially perpendicular to a face of the substrate, and spacer means for spacing the reflectors from each other at a predetermined distance, with the gain medium being sandwiched between the reflectors. The gain medium has a quantum well structure formed of a semiconductor material, and gives a gain to electromagnetic radiation by transitioning between subbands created in at least a quantum well in the quantum well structure. The spacer means is formed of a material different from a material of the gain medium.

Claims

1. A device for generating or detecting electromagnetic radiation, said device comprising:

a substrate;

a gain medium provided on the substrate, said gain medium having a quantum well structure formed of a semiconductor material, and said gain medium giving a gain to electromagnetic radiation by transitioning between subbands created in at least a quantum well in the quantum well structure;

a plurality of reflectors for confining electromagnetic radiation at a predetermined frequency range and substantially perpendicular to a face of the substrate; and

spacer means for spacing the reflectors from each other at a predetermined distance, with the gain medium being sandwiched between the reflectors, said spacer means being formed of a material different from a material of the gain medium.

2. The device according to claim 1, wherein said spacer means is composed of a layer of crystalline material systems different from the material of the gain medium.

3. The device according to claim 1, wherein said substrate also functions as the spacer means.

4. The device according to claim 1, wherein said gain medium has a resonant tunneling structure that can generate the gain for electromagnetic radiation by photon-assisted intersubband transition between quantum wells.

5. The device according to claim 1, wherein said gain medium is selectively provided in a region between the reflectors, at which the amplitude of electromagnetic radiation is relatively large.

6. The device according to claim 1, further comprising current injecting means for injecting current into the gain medium between the reflectors so that electromagnetic radiation can be generated.

7. The device according to claim 1, wherein the device is constructed so that when the device is biased below an oscillation threshold, the device can detect the intensity of electromagnetic radiation incident thereon based on a change in the bias voltage or current caused by absorption of the incident electromagnetic radiation thereby.

8. The device according to claim 1, wherein the device is constructed so that when it is biased below and nearly close to an oscillation threshold, the device can amplify the intensity of electromagnetic radiation incident thereon.

9. A sensing apparatus for sensing characteristics of an object, said sensing apparatus comprising:

a generating device for generating electromagnetic radiation; and

a detecting device for detecting electromagnetic radiation, said detecting being arranged so as to detect electromagnetic radiation reflected by or transmitted through an object irradiated with electromagnetic radiation generated by the generating device,

wherein at least one of the generating device and the detecting device is the device for generating or detecting electromagnetic radiation as recited in claim 1.

10. A method of fabricating the device for generating or detecting electromagnetic radiation as recited in claim 1, said method comprising the steps of:

growing a semiconductor heterostructure with a gain medium on a first semiconductor substrate in an epitaxial manner;

forming a spacer layer on the epitaxial-grown layer to establish a predetermined distance from a surface of the epitaxial-grown layer;

forming a first reflective mirror on a surface of the spacer layer;

bonding a surface of the first reflective mirror to a second semiconductor substrate;

removing the first semiconductor substrate; and

forming a second reflective mirror on a surface of the semiconductor exposed by removing the first semiconductor substrate.