Optimization of amplifiers for monolithic active pixel sensors

High precision particle tracking and imaging applications require position sensitive detectors with high granularity, good radiation tolerance, low material budget, fast read-out and low power dissipation. Monolithic Active Pixel Sensors (MAPS) [1] fabricated in a standard microelectronic technology provide an attractive solution for these demanding applications. The signal-to-noise ratio of MAPS can be increased by using in-pixel ampli ers. The compromise between speed, noise, gain and power consumption has to be achieved in the design of the ampli er. The charge collection ef ciency and total capacitance at the ampli er input is in uenced by the size of charge collecting diode. Therefore, in order to achieve better MAPS performances, both the geometry of the charge collecting diode and the ampli er design have to be considered in the optimization process. In this work different ampli er designs and geometries of the charge collecting diode are proposed. The characterization measurements of the ampli ers fabricated in 0.35 μm technology will be presented. The electronic properties of the ampli ers calculated with Spectre circuit simulator [2] and the charge collection ef ciency simulated with ISE-TCAD package [3] will be compared with the measurements. The advantages and drawbacks of the implemented designs will be discussed.