Silicide Schottky-Barrier Phototransistor Integrated in Silicon Channel Waveguide for In-Line Power Monitoring

An in-line power monitor with a thin nickel silicide layer placed on a silicon channel waveguide for optical absorption is proposed. A two-terminal Schottky-barrier collector phototransistor configuration is used to amplify significantly the primary photocurrent, and the Ni silicide thickness is thinned down to ~5 nm using a two-step rapid thermal annealing procedure to reduce the insertion loss. The demonstrated in-line detectors exhibit ~24-mA/W responsivity around 1550 nm with the insertion loss of ~0.8-1.2 dB. The approaches to further increase the responsivity and simultaneously decrease the insertion loss are addressed.