DESIGN, FABRICATION, AND PERFORMANCE OF HIGH-SPEED MONOLITHICALLY INTEGRATED INALAS INGAAS/INP MSM/HEMT PHOTORECEIVERS/

A detailed study of the performance of monolithically integrated photo receivers based on metal-semiconductor-metal (MSM) photodetectors (PD' s) and HEMT's is undertaken, Two different stacked-layer approaches to integrating MSM-PD's with HEMT's are investigated, and the performanc e of detectors and HEMT's for each approach is compared, The structure with the MSM layers grown on top of the HEMT layers exhibited the bes t overall performance, A physics-based MSM model is developed and inco rporated into microwave circuit design software; excellent agreement b etween circuit simulations and measured frequency responses is demonst rated, To evaluate the effects of MSM electrode geometry and detector area on photoreceiver performance, photoreceivers with MSM interelectr ode spacings of 1, 1.5, and 2 mu m were fabricated and characterized, The electrical amplifier used in the photoreceivers is a two-stage, va riable-transimpedance amplifier with a common-gate HEMT as the feedbac k path, By adjusting the de voltage applied to the gate of this feedba ck HEMT, transimpedances ranging from 55.8 to 38.1 dB Omega, with corr esponding -3 dB cutoff frequencies from 63 to 18.5 GHz, were measured experimentally, Excellent noise performance has been measured, with av erage input noise current spectral densities of 7.5, 8, and 12 pA/Hz(1 /2) obtained for bandwidths of 6.3, 8, and 13.7 GHz, respectively, A p ackaged receiver has been tested at 5 Gb/s and an open eye pattern obt ained.