Novel Silicon Photomultiplier With Vertical Bulk-Si Quenching Resistors

A novel structure of silicon photomultiplier (SiPM) is reported. In this structure, a vertical bulk-Si quenching resistor is introduced to replace the poly-Si resistor in the SiPM cell, which can help to improve the fill factor of the SiPM for more efficient photon detection. A current-blocking layer is inserted into the resistor layer to reduce the cross-section of the resistor so that the necessary high quenching resistance can be achieved by the thin resistor layer. The performance of the SiPM cell is confirmed by simulation. The vertical bulk-Si resistors are fabricated and characterized. According to the I-V measurements, the structures achieved show good resistor properties. An equivalent quenching resistance in the order of 10⁵ Ω is observed in a 1-μm-thick resistor.