PHOTOSENSORS INCLUDING PHOTODIODE CONTROL ELECTRODES AND METHODS OF OPERATING SAME

• US 20110156105A1
• Filed: 03/07/2011
• Published: 06/30/2011
• Est. Priority Date: 06/07/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Ahn, Jung-chak, Kim, Yi-tae
• Granted Patent: US 8,624,309 B2
• Time in Patent Office: Days
• US Class Current: 257/222
• CPC Class Codes: H01L 31/103 the potential barrier being of the PN homojunction type
• CPC Class Codes: H04N 25/626 Reduction of noise due to residual charges remaining after image readout, e.g. to remove ghost images or afterimages
• CPC Class Codes: H04N 25/63 applied to dark current
• CPC Class Codes: H04N 25/77 Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components

Abstract

A sensor includes a substrate, a floating diffusion node in the substrate, a photodiode in the substrate laterally spaced apart from the floating diffusion region and a transfer transistor coupling the photodiode and the floating diffusion region. The sensor further includes a photodiode control electrode disposed on the photodiode and configured to control a carrier distribution of the photodiode responsive to a control signal applied thereto. The floating diffusion region may have a first conductivity type, the photodiode may include a first semiconductor region of a second conductivity type disposed on a second semiconductor region of the first conductivity type, and the photodiode control electrode may be disposed on the first semiconductor region. The photodiode may be configured to receive incident light from a side of the substrate opposite the photodiode control electrode. The transfer transistor may include a gate electrode on a channel region in the substrate and the photodiode control electrode and the transfer transistor gate electrode may be separately controllable. In further embodiments, the photodiode control electrode comprises an extension of the transfer transistor gate electrode.

Claims

1. A sensor comprising:

a substrate;

a floating diffusion node in the substrate;

a photodiode in the substrate laterally spaced apart from the floating diffusion region;

a transfer transistor coupling the photodiode and the floating diffusion region; and

a electrode disposed on the photodiode to apply a control signal, wherein the photodiode is configured to receive incident light from a side of the substrate opposite the photodiode control electrode.