Lateral p-i-n photodetectors with 18 GHz bandwidth at 1.3 μmwavelength and small bias voltages

摘要

Simultaneous n-type and p-type diffusion, compositional mixing,and formation of ohmic contacts have been used in the fabrication oflateral p-i-n photodetectors for short (0.85 μm) and long (1.3 μmand 1.5 μm) wavelengths. Zinc-doped tungsten and MoGe₂ areused for the p-type and n-type contacts, doping, and compositionalmixing using rapid thermal processing at ≃750° C. Withstructures utilizing GaAs and Ga_0.47In_0.53Asactive regions, 3 dB bandwidths exceeding 7.5 GHz and 18.0 GHz,respectively, have been achieved at bias voltages of ≃5 V. Thecorresponding dark currents are sub-100 pA and sub-10 nA and the devicesexhibit a large dynamic range, near-ideal responsivity, and a highsensitivity. The performance, ease of fabrication, and processcompatibility make these devices suitable for integration in digitalcircuits using FET