Image sensor including transfer gates with projections extending from the sidewalls and method of fabricating the same

#This patent document claims the priority and benefits of Korean Patent Application No. 10-2017-0163392 filed on Nov. 30, 2017 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

#Various embodiments generally relate to a semiconductor device fabrication technology, and more particularly, to an image sensor and a method of fabricating the same.

#An image sensor is a device which receives light from an optical image or one or more objects and converts the received light into electrical signals forming an image. Recently, with the development of the computer industry and communication industry, the demand for an image sensor having improved performance is increasing in various fields or applications, including, e.g., a digital camera, a camcorder, a portable device such as a personal communication system, a game machine, a security camera, a medical micro-camera and a robot.

#FIGS. 1 to 3 are views illustrating a representation of an example of an image sensor in accordance with a first embodiment of the present disclosure.

#FIGS. 4 to 6 are views illustrating a representation of an example of an image sensor in accordance with a second embodiment of the present disclosure.

#FIGS. 7 to 9 are views illustrating a representation of an example of an image sensor in accordance with a third embodiment of the present disclosure.

#The disclosed image sensing technology can be implemented to provide a pixel biasing apparatus or circuit in an image sensor device, including, e.g., image sensing devices with CMOS image sensors, with an improved performance. An image sensor array is provided, for example, to respond to light which forms an image of a scene on the array. In some implementations, the image sensor array includes a plurality of pixel blocks of adjacent individual pixels, and each pixel within a pixel block includes a photosensor that operates to respond to received light to generate electric charges, a charge storage region (for example, a floating diffusion region) to store the generated electric charges, and a charge transfer region (for example, a transfer transistor) to transfer the electric charges to the charge storage region. The photosensor may be implemented to include a photogate, a photodiode, a phototransistor, a photoconductor, or a photosensitive structure capable of generating photo-generated charges. The charge transfer region may be formed to be connected to the photosensor to transfer the electric charges generated by the photosensor to the charge storage region. The disclosed technology can be used to improve a performance of an image sensor by addressing interferences occurring between adjacent charge transfer regions in a pixel block and increasing the light-to-charge conversion gain.

#The following embodiments and examples of the disclosed technology are provided to described various features of an image sensor with improved performance and a method of fabricating the same. The image sensor with the improved performance based on the disclosed technology may be implemented in one or more device configurations that are capable of preventing an interference from occurring between adjacent transfer gates and increasing a conversion gain. To this end, the following embodiments may provide an image sensor including transfer gates each having at least one projection, and a method of fabricating the same. Moreover, the following embodiments may provide an image sensor including a floating diffusion formed through a self-alignment process using transfer gates having projections and spacers formed on the sidewalls of them, and a method of fabricating the same.

#FIGS. 1 to 3 are views illustrating a representation of an example of an image sensor in accordance with a first embodiment of the disclosed technology. FIG. 1 is a top view illustrating a pixel block, and FIG. 2 is a sectional view taken along the line I-I′ of FIG. 1. FIG. 3 is of sectional views taken along the lines II-II′ and of FIG. 1.