High-frequency metamorphic p-i-n photodiodes and high-electron mobility transistor transimpedance amplifiers:: Candidates for fiber-optic communications

Solid source molecular-beam epitaxy was used to grow metamorphic films on GaAs substrates for optical (1.55 mut) p-i-n photodetectors and transimpedance amplifiers which are key components in a fiber-optic receiver. The p-i-n device structure incorporated an In0.53Ga0.47As photoabsorption layer while the transimpedance amplifier contained a metamorphic high-electron mobility transistor structure with an In0.60Ga0.40As channel layer. All layers were arsenide based which simplified material growth. A 10-mum-diam photodiode exhibited a - 3 d13 bandwidth of 52 GHz, a responsivity of 0.52 A/W corresponding to an external quantum efficiency of 42%, and a dark current of 7 nA at a 10 V reverse bias. The transimpedance amplifier demonstrated a power gain of 16 dB with a - 3 dB bandwidth of 45 GHz. The transistors in the amplifier exhibited a dc reliability of 3 x 10(6) h at 125degreesC. These performances are very promising for the application of metamorphic devices in the next generation 40 Gbit/s fiber-optic communication system. (C) 2002 American Vacuum Society.