Partial Buried Channel Transfer Device for Image Sensors

• Main Authors: Chen, Gang, Ku, Keh-Chiang, Rhodes, Howard E, Qian, Yin, Xiong, Zhibin, Hu, Sing-Chung, Bikumandla, Manoj, Tai, Hsin-Chih, Mao, Duli, Zheng, Wei, Venezia, Vincent
• Format: Patent
• Language: English; French; German
• Published: 28.02.2018
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; SEMICONDUCTOR DEVICES

An image sensor pixel (400) includes a photosensitive element (410), a floating diffusion region (415), and a transfer device (425). The photosensitive element is disposed in a substrate layer (420) for accumulating an image charge in response to light. The floating diffusion region is dispose in the substrate layer to receive the image charge from the photosensitive element. The transfer device is disposed between the photosensitive element and the floating diffusion region to selectively transfer the image charge from the photosensitive element to the floating diffusion region. The transfer device includes a buried channel device including a buried channel gate (440) disposed over a buried channel dopant region (450). The transfer device also includes a surface channel device including a surface channel gate (445) disposed over a surface channel region (455). The surface channel device is in series with the buried channel device. The surface channel gate has the opposite polarity of the buried channel gate.