A Low-Power Silicon-on-Insulator Photodetector with a Nanometer-Scale Wire for Highly Integrated Circuit

A highly sensitive photodetector, which is fabricated on a silicon-on-insulator metal oxide semiconductor field-effect transistor (SOI MOSFET) with a nanometer-scale wire, is proposed and optical responses are studied. Experimental results show that our device has a responsivity of 36 A/W, which is significantly higher than that of the conventional SOI MOSFET, and a significantly lower dark current. Interestingly, the photodetector with wire also shows pseudo kinks in a fully depleted type. We consider that these phenomena are affected by the wire, and the physical mechanism of the operation of our photodetector is explained by a strong lateral bipolar action. The linearity with optical power and spectral response in the visual spectral range are presented. Our device can be easily downscaled below 0.1 µm without the loss of sensitivity and the increase in dark current.