Light-sensing device

• US 7,521,737 B2
• Filed: 03/02/2005
• Issued: 04/21/2009
• Est. Priority Date: 09/19/2002
• Status: Active Grant

• Current Assignee: Quantum Semiconductor LLC
• Original Assignee: Quantum Semiconductor LLC
• Inventors: Augusto, Carlos J. R. P.
• Primary Examiner(s): Lee; Eugene
• Application Number:
  US11/070,721
• Publication Number:
  US 20050167709A1
• Time in Patent Office: 1,511 Days
• Field of Search: 257/184, 257/186, 257/458, 257/233, 257/438, 257/440, 257/444, 257/465, 257/466, 257/292, 257/E31.063
• US Class Current: 257/233
• CPC Class Codes: H01L 27/14609 Pixel-elements with integrated switching, control, storage or amplification elements scanning details of imagers (circuitry of solid-state image sensors H04N25/00); circuitry of imagers H04N25/70
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H01L 27/14665 Imagers using a photoconductor layer
• CPC Class Codes: H01L 27/14669 Infrared imagers
• 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 31/107 the potential barrier working in avalanche mode, e.g. avalanche photodiodes
• CPC Class Codes: H01L 31/1075 in which the active layers, e.g. absorption or multiplication layers, form an heterostructure, e.g. SAM structure

Abstract

A method of fabricating light-sensing devices including photodiodes monolithically integrated with CMOS devices. Several types of photodiode devices (PIN, HIP) are expitaxially grown in one single step on active areas implanted in a common semiconductor substrate, the active areas having defined polarities. The expitaxially grown layers for the photodiode devices may be either undoped or in-situ doped with profiles suitable for their respective operation. With appropriate choice of substrate materials, device layers and heterojunction engineering and process architecture, it is possible to fabricate silicon-based and germanium-based multi-spectral sensors that can deliver pixel density and cost of fabrication comparable to the state of the art CCDs and CMOS image sensors. The method can be implemented with epitaxially deposited films on the following substrates: Silicon Bulk, Thick-Film and Thin-Film Silicon-On-Insulator (SOI), Germanium Bulk, Thick-Film and Thin-Film Geranium-On-Insulator (GeOI).

Claims

1. A light-sensing device comprising a semiconductor substrate and photodiodes formed thereon, wherein the semiconductor substrate includes side-by-side active areas implanted therein and CMOS devices, said active areas having a defined polarity and said active areas being electrically isolated from one another and from the adjacent CMOS device by isolation regions, the photodiodes comprising photodiodes of a first type and of a second type, the photodiodes of the first and second types being formed in one single epitaxial growth step on said active areas.

2. A light-sensing device as claimed in claim 1, wherein the substrate is made of a material selected from the group comprising Silicon Bulk substrates, or Thick-Film Silicon-On-Insulator (SOI), or Thin-Film Silicon-On-Insulator (SOI), or Germanium Bulk substrates, or Thick-Film Germanium (GeOI), or Thin-Film Germanium-On-Insulator (GeOI).

3. A light-sensing device as claimed in claim 1, wherein the active areas are the bottom electrodes of epitaxially grown photodiodes.

4. A light-sensing device as claimed in claim 1, wherein the surface of the active areas is corrugated.

5. A light-sensing device as claimed in claim 1, wherein the epitaxially grown layers of the photodiodes are in contact with the side edges of the active areas underneath.

6. A light-sensing device as claimed in claim 1, wherein the epitaxially grown layers of the photodiodes cover the top edges of the isolation areas placed between active areas.

7. A light-sensing device as claimed in claim 1, wherein the bottom electrode and the epitaxial layers comprising a middle region and a top electrode, form devices operating in avalanche mode, such as Avalanche Photo-Diodes.

8. A light-sensing device comprising a semiconductor substrate and photodiodes formed thereon, wherein the semiconductor substrate includes side-by-side active areas implanted therein and CMOS devices, said active areas having a defined polarity and said active areas being electrically isolated from one another and from the adjacent CMOS device by isolation regions, the photodiodes comprising photodiodes of a first type and of a second type, the photodiodes of the first and second types being formed in one single epitaxial growth step on said active areas, wherein the photodiodes of the first type are grown on active areas having a predetermined first polarity and the photodiodes of the second type being grown on active areas having a second polarity that is opposite to said first polarity.

9. A light-sensing device as claimed in claim 8, wherein the substrate is made of a material selected from the group comprising Silicon Bulk substrates, or Thick-Film Silicon-On-Insulator (SOI), or Thin-Film Silicon-On-Insulator (SOI), or Germanium Bulk substrates, or Thick-Film Germanium (GeOI), or Thin-Film Germanium-On-Insulator (GeOI).

10. A light-sensing device as claimed in claim 8, wherein the active areas are the bottom electrodes of epitaxially grown photodiodes.

11. A light-sensing device as claimed in claim 8, wherein the surface of the active areas is corrugated.

12. A light-sensing device as claimed in claim 8, wherein the epitaxially grown layers of the photodiodes are in contact with the side edges of the active areas underneath.

13. A light-sensing device as claimed in claim 8, wherein the epitaxially grown layers of the photodiodes cover the top edges of the isolation areas placed between active areas.

14. A light-sensing device as claimed in claim 8,wherein the bottom electrode and the epitaxial layers comprising a middle region and a top electrode, form devices operating in avalanche mode, such as Avalanche Photo-Diodes.