Patent ID: 7998782
Filing Date: 2011-08-16
Classification: H01L

Abstract:
1. A method of fabricating an image sensor, comprising: forming an isolation structure for defining a first active region of a semiconductor substrate; forming a first transistor of a unit pixel in the first active region; forming a second transistor of the unit pixel in the first active region; and forming a threshold voltage lowering region in a portion of the semiconductor substrate near a portion of the isolation structure abutting the second transistor in the first active region, wherein the threshold voltage lowering region causes the second transistor to have a respective threshold voltage magnitude that is lower than for the first transistor, and wherein said threshold voltage lowering region is formed in a portion of said semiconductor substrate along a first side of a gate of said second transistor, and wherein any source/drain region of said second transistor is formed along a second side of said gate that is along a different direction from said first side of said gate.