Effects of Rapid Thermal Annealing on the Device Characteristics of Quantum Well Infrared Photodetectors.

The effect of rapid thermal annealing (RTA) on important detector characteristics such as dark current, absolute response, noise, and detectivity is investigated for quantum-well infrared photodetectors (QWIP) operating in the 8–12 µm wavelength regime. A comprehensive set of experiments is conducted on QWIPs fabricated from both as-grown and annealed multiple-quantum-well structures. RTA is done at an anneal temperature of 850°C for 30 s using an SiO₂ encapsulant. In general, a decrease in performance is observed for RTA QWIPs when compared to the as-grown detectors. The peak absolute response of the annealed QWIPs is lower by almost a factor of four, which results in a factor of four decrease in quantum efficiency. In addition, a degraded noise performance results in a detectivity which is five times lower than that of QWIPs using asgrown structures. Theoretical calculations of the absorption coefficient spectrum are in excellent agreement with the experimental data. [ABSTRACT FROM AUTHOR]