UNIT PIXEL IN IMAGE SENSOR AND METHOD FOR MANUFACTURING THEREOF

PURPOSE: A unit pixel of an image sensor and a manufacturing method thereof are provided to uniformly apply bias on the whole photo diode by forming a diffusion region at the center of a photo diode. CONSTITUTION: A circular active area(30) is formed on a semiconductor substrate(10) by a circular field area(20). A first element isolation film(21) and a second element isolation film(22) are separated at first breadth. A transfer transistor(50) is formed at the center of the active area in the shape of a ring. A photo diode(90) is formed in the active area corresponding to the outside of the transfer transistor. A floating diffusion area(110) is formed in the active area corresponding to the inside of the transfer transistor.