Isolation techniques for reducing dark current in CMOS image sensors
AssigneeMicron Technology, Inc.
InventorsChandra Mouli, Howard Rhodes
Life of this patent
Estimating the term…
Abstract
Isolation methods and devices for isolating regions of a semiconductor device. The isolation method and structure include forming an isolating trench in an active area and filling the trench with a doped conductive material containing silicon. Suitable conductive materials containing silicon include polysilicon and silicon-germanium. There is also provided a method and structure for isolating the regions by providing a trench in an active area of a substrate, growing an epitaxial layer in the trench to fill the trench or to partially fill the trench and depositing an insulating material over the epitaxial layer and within the trench to completely fill the trench.
Claims24
A method of forming an image sensor, said method comprising the steps of:
- forming a substrate;
- forming an active layer of a first conductivity type within said substrate;
- forming a charge transfer region within said active layer;
- forming a photodiode within said active layer adjacent said charge transfer region, said step of forming said photodiode comprising forming a region of a second conductivity type between regions of said active layer of said first conductivity type;
- forming a charge collection region within said active layer for receiving charges transferred from said photodiode region;
- and
- forming an isolation region adjacent said active layer, by forming a trench at least partially filling said trench with a conductive material.
A method of forming an image sensor, said method comprising the steps of:
- forming a trench in a substrate between adjacent pixels;
- forming an insulating liner formed along at least one wall of said trench;
- forming an epitaxial layer in contact with said substrate at a bottom surface of said trench;
- and
- forming a conductive material over said epitaxial layer and within said trench.
Dependencies are inferred from the claim text.