Monolithic heteroepitaxial PbTe-on-Si infrared focal plane arraywith 96×128 pixels

A two-dimensional (2-D) infrared focal plane array in a heteroepitaxial narrow gap semiconductor layer has been realized for the first time on a Si substrate containing the read-out electronics. The infrared-sensitive layer (PbTe for the 3-5 μm wavelength range) is grown by molecular beam epitaxy at temperatures below 415°C, allowing fully processed and tested Si chips to be employed. Individual pixels are obtained by mesa-etching, and photovoltaic sensors are fabricated with standard photolithographic techniques. Within the >97% operational pixels, high quantum efficiencies and differential resistances at zero bias up to several 100 kΩ at 95 K are observed