Crosstalk resistant integrated Uni-Traveling Carrier Photodetector

Uni-traveling carrier (UTC) photodetectors are pivotal as photomixers in THz transmission systems owing to their high-speed and output power in the THz range. However, for an efficient transmitter, the laser, modulator, signal processing, and maybe even the amplification has to be integrated on the same chip. This might lead to problems with the thermal crosstalk induced by the thermally conductive chip components. Such crosstalk can severely reduce the performance of the UTC photodetector with regard to the dark current, bandwidth, and data transmission. Here, we show how a deep trench can reduce the thermal crosstalk for a UTC photodetector in densely packed circuits, which in turn reduces the dark current and device capacitance and thus, improves the performance.