Buried, fully depletable, high fill factor photodiodes

• US 20050064617A1
• Filed: 11/09/2004
• Published: 03/24/2005
• Est. Priority Date: 02/10/1997
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Bart Dierickx
• Inventors: Dierickx, Bart
• Granted Patent: US 7,253,019 B2
• Time in Patent Office: Days
• US Class Current: 438/48
• CPC Class Codes: H01L 27/1443 with at least one potential jump or surface barrier
• CPC Class Codes: H01L 27/14601 Structural or functional details thereof
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H01L 31/0352 characterised by their shape or by the shapes, relative sizes or disposition of the semiconductor regions
• CPC Class Codes: H04N 3/155 Control of the image-sensor operation, e.g. image processing within the image-sensor

Abstract

A semiconductor detector of electromagnetic radiation which utilizes a dual-purpose electrode which extends significantly beyond the edge of a photodiode. This configuration reduces the sensitivity of device performance on small misalignments between manufacturing steps while reducing dark currents, kTC noise, and “ghost” images. The collection-mode potential of the dual-purpose electrode can be adjusted to achieve charge confinement and enhanced collection efficiency, reducing or eliminating the need for an additional pinning layer. Finally, the present invention enhances the fill factor of the photodiode by shielding the photon-created charge carriers formed in the substrate from the potential wells of the surrounding circuitry.

Claims

1. A method of making a detector of electromagnetic radiation comprising:

providing a semiconductor substrate with dopants of a first conductivity type at a first concentration density, and with an insulating layer at its surface;

forming a collection region by introducing dopants of a second conductivity type which is opposite the first conductivity type at a second concentration density region into the surface region of the semiconductor substrate; and

forming a detection region not bordering the collection region which defines a barrier region between the detection region and the collection region by introducing dopants of the second conductivity type at a third concentration density into the surface region of the semiconductor substrate;

forming a dual-purpose electrode on the insulating layer with the dual-purpose electrode extending over the surface of the collection region, and fully across the barrier region to the edge of the detection region.