3D integration of Geiger-mode avalanche photodiodes aimed to very high fill-factor pixels for future linear colliders

This paper presents an analysis of the maximum achievable fill-factor by a pixel detector of Geiger-mode avalanche photodiodes with the Chartered 130nm/Tezzaron 3D process. The analysis shows that fill-factors between 66% and 96% can be obtained with different array architectures and a time-gated readout circuit of minimum area. The maximum fill-factor is achieved when the two-layer vertical stack is used to overlap the non-sensitive areas of one layer with the sensitive areas of the other one. Moreover, different sensor areas are used to further increase the fill-factor. A chip containing a pixel detector of the Geiger-mode avalanche photodiodes and aimed to future linear colliders has been designed with the Chartered 130nm/Tezzaron 3D process to increase the fill-factor. •GAPD pixel detectors present a low detection efficiency due to a reduced fill-factor.•3D-ICs are proposed as a solution to increase the fill-factor of GAPD detectors.•The maximum achievable fill-factor by a GAPD detector in a 3D-IC process is analyzed.•Fill-factors between 66% and 96% can be obtained with different array architectures.•The array is operated in a time-gated mode to reduce the expected sensor noise.