High-speedmonolithicallyintegratedMSM-FETphotoreceiver based on GaAs/InGaAs strained layer superlattice

Abstract

We report, for the first time, the realization of a long-wavelength monolithically integrated MSM-FET photoreceiver using a GaAs/InGaAs strained layer superlattice (SLS) as the photoabsorbing layer of the detector. The channel of the MESFET, made from an n-doped GaAs layer, is grown above the SLS after a thin intermediate, GaAs/AlGaAs superlattice, smoothing layer. The MSM photodiodes exhibited a very low dark current, 26 nA at 10 V bias, a very fast pulse response with FWHM of about 42 ps. The photoreceivers, consisting of an MSM detector and a single stage amplifier, exhibited a very fast impulse response with FWHM, rise time and fall time of 105, 44 and 130 ps, respectively. By assuming a gaussian pulse, these correspond to a bandwidth in excess of 4.5GHz.