A bipolar PIN phototransistor with modulated base doping

AbstractA new CMOS-based p+np−p+ phototransistor utilizing a modulated base doping is presented. Furthermore, the collector of the device is formed by a thick low-doped p− region. Both measures lead to excellent responsivity values of 12.2, 46.5, 46.9 and 41.9 A/W at wavelengths of 405, 675, 785 and 855 nm, respectively. A detector with a light-sensitive area of 50 μm in square reaches a −3 dB bandwidth of 4.2 MHz at 3 V collector-emitter voltage at 850 nm