A grazing angle technique to measure the charge collection efficiency for CMOS Active Pixel Sensor

Recently, CMOS Monolithic Active Pixels Sensors have become strong candidates as pixel detectors to be used in high energy physics experiments. A very good spatial resolution and an excellent detection efficiency could be obtained with these detectors. Beside spatial resolution and detection efficiency, an important parameter to be investigated is the charge collection efficiency (CCE) as a function of the distance from the detector surface. In this paper a new approach to measure the CCE profile by mean of ionizing particles is proposed.

Fig 1. Grazing Angle method to perform the CCE measurement; Fig 2. Charge collection profile for an epitaxial CMOS APS sensor