Abstract: This paper reports a front-illuminated planar InGaAs PIN photodiode with very low dark current, very low capacitance and very high responsivity on S-doped InP substrate. The presented device which has a thick absorption layer of 2.92μm and a photosensitive area 73μm in diameter exhibited the high performance of a very low capacitance of 0.47pF, a very low dark current of 0.041nA, a very high responsivity of 0.99A/W (79% quantum efficiency) at λ =1.55μm, the 3dB bandwidths of 6.89GHz (−5V), 7.48GHz (−12V) for bare chips and 4.48GHz (−5V), 5.02GHz (−12V) for the devices packaged in TO can, respectively. Furthermore, the developed PIN photodiodes possess high breakdown voltage of less than −25V. [Copyright &y& Elsevier]