The design, fabrication. and characterization of a 0.85-μm sensitive photoreceiver is described. The monolithically integrated optoelectronic receiver is based on pseudomorphic InGaAs on GaAs modulation-doped field-effect transistors (MODFET’s) and metal-semiconductor-metal (MSM) photodectectors. High-performance quarter-micrometer MODFET’s withf1’s of -∼70 GHz are utilized in a two-stage transimpedance amplifier. An asymmetric and a symmetric amplifier design are compared. The symmetric design is found to provide the desired zero dc offset voltage for a variety of supply voltages. Excess MSM-detector dark current and low-frequency internal gain are greatly reduced through the use of a silicon nitride passivation layer and/or AlGaAs cap layer. Receiver transimpedances between 100 and 5000 Ω are obtained by varying the bias on an active feedback resistor. The parasitic capacitances of this common-gate feedback FET are studied. A transimpedance amplifier bandwidth as high as 14 GHz and an overall photoreceiver bandwidth of 11 GHz are measured. These are the highest bandwidths yet reported for any monolithic OEIC receiver.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering