Sub 0.01pH Resolution Extended Gate Type pH Image Sensor with Charge Accumulation Function

In this study, we designed and evaluated a new extended gate pH image sensor with accumulation function circuits as a state-of-the-art bio-image sensor. The accumulation function circuit can be expected to amplify the signal by repeatedly transferring the signal charge from the pixel to the capacitor, and to improve the pH resolution from the viewpoint of the signal to noise ratio (SNR). From the measurement results, this image sensor achieved a pH sensitivity of 210 mV / pH and a pH resolution of 0.0099 pH at a single pixel and four times of accumulation. These results indicate the future realization of an image sensor capable of imaging the activity of biological cells with pH resolution of 0.01 pH.