Optical and electrical characteristics of 1.3-mu-m interdigitated-metal-semiconductor-metal (IMSM) photodetectors on a thermally stable, superlattice-enhanced InGaAs/GaAs structure are reported. Photodetectors fabricated on material that was subjected to a rapid thermal anneal have high internal quantum efficiency and a measured bandwidth of 14 GHz. This structure has the potential for fabrication of low-cost, long-wavelength, monolithic receiver circuits based on GaAs MESFET technology.