EFFECTS OF RAPID THERMAL ANNEALING ON THE DEVICE CHARACTERISTICS OF QUANTUM-WELL INFRARED PHOTODETECTORS

The effect of rapid thermal annealing (RTA) on important detector char acteristics such as dark current, absolute response, noise, and detect ivity is investigated for quantum-well infrared photodetectors (QWIP) operating in the 8-12 mu m wavelength regime. A comprehensive set of e xperiments is conducted on QWIPs fabricated from both as-grown and ann ealed multiple-quantum-well structures. RTA is done at an anneal tempe rature of 850 degrees 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 QW IPs is lower by almost a factor of four, which results in a factor of four decrease in quantum efficiency. In addition, a degraded noise per formance results in a detectivity which is five times lower than that of QWIPs using as grown structures. Theoretical calculations of the ab sorption coefficient spectrum are in excellent agreement with the expe rimental data.