CMOS Image Sensor and Method for Manufacturing the Same

Abstract

A CMOS image sensor and a fabrication method thereof are provided. The CMOS image sensor includes a semiconductor substrate having an active area and an isolation area; a photodiode area and a transistor area defined on the active area; a plurality of semiconductor patterns formed on the photodiode area; a transistor formed on the transistor area; a first conductive type first diffusion region formed on the photodiode area; a first conductive type second diffusion region formed on the transistor area; and a second conductive type third diffusion region formed on the first diffusion region.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an equivalent circuit diagram illustrating a 4T-type CMOS image sensor according to a related art.

FIG. 2 is a layout view showing a unit pixel of a 4T-type CMOS image sensor according to the related art.

FIGS. 3A to 3E are sectional views taken along line I-I′ of FIG. 2 to illustrate a procedure for fabricating a CMOS image sensor according to the related art.

FIG. 4 is a sectional view showing a CMOS image sensor according to an embodiment of the present invention.

FIGS. 5A to 5F are sectional views illustrating a procedure for fabricating a CMOS image sensor according to an embodiment of the present invention.

Claims

1. A CMOS image sensor comprising: a photodiode area and a transistor area defined on an active area of a semiconductor substrate;a plurality of semiconductor patterns formed on the photodiode area;a transistor formed on the transistor area;a first diffision region of a first conductive type formed on the photodiode area;a second diffusion region of the first conductive type formed on the transistor area; anda s third diffusion region of a second conductive type formed on the first diffusion region.

2. The CMOS image sensor according to claim 1, wherein the plurality of semiconductor patterns have heights identical to each other.

3. The CMOS image sensor according to claim 1, wherein the plurality of semiconductor patterns are formed having a constant interval therebetween.

4. The CMOS image sensor according to claim 1, wherein the transistor comprises a transfer transistor.

5. The CMOS image sensor according to claim 1, wherein the transistor comprises a gate insulating layer, a gate electrode formed on the gate insulating layer, and insulating layer sidewalls formed at both sides of the gate electrode.

6. The CMOS image sensor according to claim 1, wherein the plurality of semiconductor patterns are formed of an epitaxial layer of the second conductive type.

7. A method for fabricating a CMOS image sensor, comprising: forming a plurality of semiconductor patterns on a photodiode area of an active area of a semiconductor substrate;forming a gate insulating layer and a gate electrode on a transistor area of the active area;forming a first diffusion region of a first conductive type on the photodiode area;forming insulating layer sidewalls at both sides of the gate electrode;forming a second diffusion region of the first conductive type on the transistor area; andforming a third diffusion region of a second conductive type on the first diffusion area.

8. The method according to claim 7, wherein the plurality of semiconductor patterns have heights identical to each other.

9. The method according to claim 7, wherein the plurality of semiconductor patterns are formed having a constant interval therebetween.

10. The method according to claim 7, wherein the plurality of semiconductor patterns comprise an epitaxial layer of the second conductive type.

11. The method according to claim 7, wherein forming the plurality of semiconductor patterns comprises forming an epitaxial layer on the photodiode area and selectively removing portions of the epitaxial layer by performing photolithography and etching processes.