Design Of A Microscope Chip Based On Floating-gate Image Sensor

In the medical field,the use of microscopes runs through nearly each aspect of many scientific researches.From the beginning of the 1990 s,almost all of current microscopes,especially optical microscopes,are inseparable from image sensor.An image sensor,or a photosensitive element,is a device that converts an optical image into an electronic signal.It has an important value in mobile phones,digital cameras and other electronic optical equipment,or in the military,aerospace,medical and other cutting-edge areas.Floating-gate image sensor is a new type of image sensor,with a special floating gate pixel unit.Its small pixel size and high full-well capacity make it possible to be applied in aerospace,microscopic areas,etc.In this paper,a microscope chip based on floating-gate image sensor is designed.The pixel unit is an improved floating gate device,and its pixel size is close to the diffraction limit of ordinary optical microscope.When it comes to same array area,the total number of pixels reaches nearly 10 times to other types of image sensors.At the same time,it can achieve high resolution,low power consumption,high dynamic range and other excellent properties.The paper first describes the basic structure and characteristics of the floating-gate device pixel unit,and demonstrates its feasibility for the microscope chip.Then it carries out the array structure and overall design of the external circuit structure based on the kind of pixel unit.After that,the design and simulation process of the key sub-modules of the peripheral circuit are described in detail.Finally,some possible problems of the system are presented,and special methods of improving the image quality are provided.The microscope chip is fabricated by 65 nm NOR-FLASH 2P3 M process.It has a pixel unit size of 400nm×200nm,and an array size of 20480×20480.Operated in a frequency of 100 MHz,it can capture 12 bit digital image.As one of image sensors with smallest pixel unit and highest integration,its effective pixels number exceeds 400 million.