Photosensor with a capacitor connected in parallel so as to increase the dynamic range and to improve the holding characteristics of the photosensor

• US 4,972,252 A
• Filed: 11/28/1989
• Issued: 11/20/1990
• Est. Priority Date: 06/25/1987
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Maekawa, Toshikazu
• Primary Examiner(s): Davie, James W.
• Application Number:
  US07/442,406
• Time in Patent Office: 357 Days
• Field of Search: 357/58, 357/51, 357/30 D
• US Class Current: 257/448
• CPC Class Codes: H01L 27/1443 with at least one potential jump or surface barrier

Abstract

A photosensor has a PIN photodiode and a piling-type capacitor is connected in parallel with the PIN photodiode so as to increase the reverse bias capacitance of the PIN photodiode so as to increase the dynamic range.

Claims

1. A photosensor comprising:

a PIN photodiode formed of a P-type semiconductor layer, an intrinsic semiconductor layer and an N-type semiconductor layer mounted on an insulating substrate;

said p-type semiconductor layer an said n-type semiconductor layer laterally offset from each other and said intrinsic semiconductor layer overlying said p-type and n-type semiconductor layers and said insulating substrate; and

a capacitor formed with a first electrode (16) connected to one (10) of said P-type semiconductor layer (11) or said N-type semiconductor layer (10) and a second electrode (15) formed over said insulating substrate and extending through an insulating layer and connected to the other one of said P-type semiconductor layer (11) or said N-type semiconductor layer (10).

2. A photosensor comprising:

a PIN photodiode formed of a P-type semiconductor layer, an intrinsic semiconductor layer and an N-type semiconductor layer mounted on an insulating substrate;

said p-type semiconductor layer and said n-type semiconductor layer laterally offset from each other and said intrinsic semiconductor layer overlying said p-type and n-type semiconductor layers and said insulating substrate; and

a capacitor formed with a first electrode (15) made of a semiconductor layer formed integrally with one of said N-type semiconductor layer or said P-type semiconductor layer and a second electrodes 16, 14 made of a wiring layer which is connected to a surface or the other one of said N-type semiconductor layer of said p-type semiconductor layer and extending through a window (13) which is formed through an insulating layer.

3. A photosensor with improved characteristics comprising an insulating substrate, a p-type semiconductor layer, an intrinsic semiconductor layer and an n-type semiconductor layer mounted on said insulating substrate;

said p-type semiconductor layer and said n-type semiconductor layer laterally offset from each other and said intrinsic semiconductor layer overlying said p-type and n-type semiconductor layers and said insulating substrate to form a PIN photodiode, a first electrode (15) connected to either said p-type semiconductor layer or said n-type semiconductor layer, an insulating layer (15) covering at least a part of said first electrode (15), and a second electrode (16) formed over said first electrode and separated therefrom by said insulating layer (5) and said second electrode (16) connected to either said n-type semiconductor layer (10) or said p-type layer (11) so as to form a capacitor which is in parallel with the internal capacitance of said PIN photodiode.