Development of new MPPC with higher NIR sensitivity and wider dynamic range

摘要

The Multi-Pixel Photon Counter (MPPC), which is also called a silicon photomultiplier (SiPM)1'2, is one promising candidate for automotive light detection and ranging (LIDAR)3. Due to high internal gain around 106, photon counting is possible and satisfies long range measurement. Compared to photo diodes (PDs) and avalanche photo diodes (APDs), read-out circuits for MPPCs are very simple because no external amplifier is needed. Conventional MPPCs have been developed for targeting blue scintillation light around 400 nm for positron emission tomography (PET) and high energy physics experiments. In this paper we report new near-infrared (NIR)-enhanced MPPCs whose development targets include 905 nm laser light for automotive LIDAR systems. Conventional MPPCs have a p-on-n structure and show 2% photon detection efficiency (PDE) at 905 nm. Our newly developed n-on-p MPPC achieved 7% PDE without greatly changing the impurity concentration profile of the depletion layer. This n-on-p MPPC has been released as an NIR-enhanced MPPC: S13720-1325CS. For further improvement of NIR sensitivity, we tried several silicon wafers and process conditions of p-n junction profiles. Even though dark noise and the voltage range have to be modified, the latest sample shows 11% PDE, suggesting potential for further sensitivity improvement.