Abstract

Monolithically integrable detectors are defined as detectors whose fabrication is completely compatible with the design rules used in the standard integrated circuit fabrication. An interdigitated electrode geometry permits both the ready integration of these detectors into electronic IC topologies and the use of a large detection area in conjunction with a low device capacitance. The large detector area improves the signal strength available for amplification, while the low capacitance extends the high-frequency bandwidth. To date, most interdigitated detectors reported in the literature are of the Schottky or photoconductive variety.¹ Unfortunately, the low channel resistance between the interdigitated fingers produces a large Johnson noise contribution in these devices which increases linearly with the frequency.² In comparison, the intrinsically high shunt resistance of a PIN diode enhances the SNR by limiting the Johnson noise contribution, thereby optimizing the detector dynamic range.

© 1986 Optical Society of America