Method for fabricating a CMOS image sensor

Abstract

A method for fabricating a CMOS image sensor may include forming an isolation layer defining an active area on a semiconductor substrate, forming first and second gate electrodes in the transistor area of the semiconductor substrate, forming a photodiode area in the semiconductor substrate at a first side of the first gate electrode, forming an oxide layer over the photodiode area, the oxide layerhaving a thickness greater than that of the dielectric layer, forming a source / drain extension area in the semiconductor substrate at a second side of the second gate electrode and between the firstand second gate electrodes, forming source / drain regions in the transistor area of the semiconductor substrate by ion implantation through the dielectric layer, and forming a complementary ion implantation region in the photodiode area through the oxide layer.

Description

technical field [0001] The present invention relates to a method for manufacturing a CMOS image sensor. Background technique [0002] Image sensors are semiconductor devices for converting light images into electrical signals, and are mainly classified into Charge Coupled Devices (CCD) and Complementary Metal Oxide Semiconductor (CMOS) image sensors. [0003] The CCD has a plurality of photodiodes (PDs) arranged in a matrix to convert optical signals into electrical signals. The CCD includes: a plurality of vertical charge-coupled devices (VCCDs), arranged between a plurality of photodiodes vertically arranged in a matrix, so that charges are transmitted in a vertical direction when charges are generated from each photodiode; a plurality of horizontal charge-coupled devices ( HCCD) for horizontally transferring charges that have been transferred from the VCCD; and a sense amplifier for outputting charges by sensing the horizontally transferred charges. [0004] However, su...

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Problems solved by technology

[0004] However, this kind of CCD has various disadvantages such as complicated drive mode, high power consumption, etc.

In addition, the CDD usually requires a multi-step photolithography process, which makes the manufacturing process of the CCD relatively complicated

[0005] In addition, because it is difficult to integrate the controller, signal processor, and analog / digital converter (A / D converter) on a single chip of the CCD, the CCD may not be suitable for small products

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