Advanced inductively coupled plasma etching processes for fabrication of resonator-quantum well infrared photodetector

• Resonator-quantum well infrared photodetectors (R-QWIPs) use resonances to increase the quantum efficiency (QE).
• The QEs observed is 70.8% in one of the test detectors.
• The test results agree with EM designs satisfactorily.
• The spectral uniformity of the FPA is about 3%.

Resonator-quantum well infrared photodetectors (R-QWIPs) are the next generation of QWIP detectors that use resonances to increase the quantum efficiency (QE). To achieve the expected performance, the detector geometry must be produced in precise specification. In particular, the height of the diffractive elements (DE) and the thickness of the active resonator must be uniformly and accurately realized to within 0.05 μm accuracy and the substrates of the detectors have to be removed totally. To achieve these specifications, two optimized inductively coupled plasma (ICP) etching processes are developed. Using these etching techniques, we have fabricated a number of R-QWIP test detectors and FPAs with the required dimensions and completely removed the substrates of the test detectors and FPAs. Their QE spectra were tested to be in close agreement with the theoretical predictions. The operability and spectral non-uniformity of the FPA is about 99.57% and 3% respectively.