Manufacturing isolation layer in CMOS image sensor

Abstract

A method of manufacturing an isolation layer in a CMOS image sensor injects oxygen and P-type ions into a device isolation region without etching damage and performs a heating process to form a device isolation layer in a semiconductor substrate. An ion injection mask layer is formed that exposes a device isolation region on a low concentration first conductive type semiconductor substrate. Oxygen ions are injected into the semiconductor substrate using the mask layer. A heating process is performed to form an oxide layer in the device isolation region. A gate insulating layer is formed on the semiconductor substrate and a gate electrode is formed on the gate insulating layer. A low concentration second conductive type diffusion region is formed in a photodiode region. A high concentration second conductive type diffusion region is formed at both sides of the gate electrode in the semiconductor substrate. A first conductive type diffusion region haying a concentration higher than that of the semiconductor substrate is formed on the low concentration second conductive type diffusion region in the semiconductor substrate.

Description

[0001] Cross References to Related Applications [0002] This application claims the benefit of Korean Patent Application No. 10-2004-0117225 filed on December 30, 2004, which is hereby incorporated by reference as if fully set forth herein. technical field [0003] The present invention relates to CMOS image sensors, and more particularly, to methods of fabricating isolation layers in CMOS image sensors. The method may implant oxygen and P-type ions into a device isolation region without suffering etching damage and perform a heating process to form a device isolation layer in a semiconductor substrate. Background technique [0004] An image sensor is a semiconductor device for converting an optical image into an electrical signal. A typical complementary metal-oxide-silicon (CMOS) image sensor includes: a charge-coupled device, where charge carriers are stored in metal-oxide-silicon capacitors in close proximity to each other; and MOS transistors corresponding to the numb...

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Problems solved by technology

When a semiconductor substrate is etched, the silicon lattice can suffer etching damage

Also, since the trench is included in the photodiode region, unnecessary interface traps are created at the interface of the STI region

Accordingly, the junction leakage current increases, and the noise characteristics of the image sensor deteriorate

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