2-4 GHz monolithic lateral p-i-n photodetector and MESFET amplifieron GaAs-on-Si

The design, fabrication, and evaluation of broadband lateral p-i-n photodetectors monolithically integrated with multistage MESFET amplifiers on GaAs-on-Si are described. Unique features of this approach are that (a) the lateral p-i-n structure is compatible with monolithic microwave integrated circuit (MMIC) technology and (b) the p-i-n detector is fabricated directly on the GaAs buffer layer without p⁺ and n⁺ implants, thus resulting in a simplified fabrication process. The operation of the circuit is compared to that of a similar circuit fabricated on a GaAs substrate. A quantum efficiency exceeding 60% has been measured for the p-i-n detectors. The 2- to 4-GHz frequency responses of one- and two-stage p-i-n/FET preamplifiers are presented. The response varies ±3 dB over the frequency band