MULTI-THICKNESS GATE DIELECTRIC

• Main Authors: Chen, Gang, Yang, Cunyu, Chen, Guannan, Tai, Dyson, Zheng, Yuanwei, Webster, Eric, Hu, Sing-Chung, Mao, Duli, Grant, Lindsay, Wang, Qin
• Format: Patent
• Language: English
• Published: 02.04.2020
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; PICTORIAL COMMUNICATION, e.g. TELEVISION; SEMICONDUCTOR DEVICES

An image sensor includes one or more photodiodes disposed in a semiconductor material to receive image light and generate image charge, and a floating diffusion to receive the image charge from the one or more photodiodes. One or more transfer transistors is coupled to transfer image charge in the one or more photodiodes to the floating diffusion, and a source follower transistor is coupled to amplify the image charge in the floating diffusion. The source follower includes a gate electrode (coupled to the floating diffusion), source and drain electrodes, and an active region disposed in the semiconductor material between the source and drain electrodes. A dielectric material is disposed between the gate electrode and the active region and has a first thickness and a second thickness. The second thickness is greater than the first thickness, and the second thickness is disposed closer to the drain electrode than the first thickness.