Method for fabricating photodiode of CMOS image sensor

• US 20060008940A1
• Filed: 07/06/2005
• Published: 01/12/2006
• Est. Priority Date: 07/08/2004
• Status: Active Grant

• Current Assignee: DONGBU ELECTRONICS CO., LTD. (DB HiTek Co., Ltd.)
• Original Assignee: Dongbuanam Semiconductor, Inc. (DB HiTek Co., Ltd.)
• Inventors: Jeon, In Gyun
• Granted Patent: US 7,354,841 B2
• Time in Patent Office: Days
• US Class Current: 438/69
• CPC Class Codes: H01L 27/14601 Structural or functional details thereof
• CPC Class Codes: H01L 27/14689 MOS based technologies

Abstract

A method for fabricating a photodiode of a CMOS image sensor is disclosed, to improve a charge accumulation capacity in the photodiode, which includes the steps of defining a semiconductor substrate as an active area and a field area by forming an STI layer; firstly implanting impurity ions for formation of the photodiode to the semiconductor substrate of the active area; secondarily implanting impurity ions for formation of the photodiode to the semiconductor substrate being adjacent to the STI layer; and forming a photodiode ion-implantation diffusion layer by diffusing the implanted impurity ions with a thermal process.

Claims

1. A method for fabricating a photodiode of a CMOS image sensor comprising:

defining a semiconductor substrate as an active area and a field area by forming an STI layer;

firstly implanting impurity ions for formation of the photodiode to the semiconductor substrate of the active area;

secondarily implanting impurity ions for formation of the photodiode to the semiconductor substrate being adjacent to the STI layer; and

forming a photodiode ion-implantation diffusion layer by diffusing the implanted impurity ions with a thermal process.

2. The method of claim 1, wherein the ion-implantation energy in the process for firstly implanting the impurity ions is identical to the ion-implantation energy in the process for secondarily implanting the impurity ions.

3. The method of claim 1, wherein the process for secondarily implanting the impurity ions includes the steps:

forming a photoresist to expose the predetermined portion of the semiconductor substrate of the active area being adjacent to the STI layer; and

implanting impurity ions for formation of the photodiode to the semiconductor substrate in state of using the photoresist as a mask.

4. The method of claim 3, wherein the predetermined portion of the semiconductor substrate of the active area being adjacent to the STI layer is exposed at a width below 0.5 μ

m by patterning the photoresist.