A 50 ps resolution monolithic active pixel sensor without internal gain in SiGe BiCMOS technology

A monolithic pixelated silicon detector designed for high time resolution has been produced in the SG13G2 130 nm SiGe BiCMOS technology of IHP. This proof-of-concept chip contains hexagonal pixels of 65 μm and 130 μm side. The SiGe front-end electronics implemented provides an equivalent noise charge of 90 and 160 e^- for a pixel capacitance of 70 and 220 fF, respectively, and a total time walk of less than 1 ns. Lab measurements with a ⁹⁰Sr source show a time resolution of the order of 50 ps. This result is competitive with silicon technologies that integrate an avalanche gain mechanism.