34 GHz bandwidth GaAs high-speed Schottky barrier photodiode fabricated by chemical-beam epitaxy

A high-speed, high-sensitivity GaAs Schottky barrier photodiode grown by chemical-beam epitaxy (CBE) has been designed, fabricated, and characterized. Antireflection coatings utilizing Si and SiO 2 films were optimally used to minimize reflection loss, thereby significantly improving sensitivity of the Schottky barrier photodiode. This device has a -3 dB cutoff frequency of 34 GHz, determined by an optical heterodyne technique, an external quantum efficiency of 41% at 780 nm wavelength, and a dark current of 100 pA ( V R =-2 V).