PROGRESS IN MOVPE OF HGCDTE FOR ADVANCED INFRARED DETECTORS

This paper reviews the significant progress made over the past five ye ars in the development of metalorganic vapor phase epitaxy (MOVPE) for the in situ growth of HgCdTe p-njunction devices for infrared detecto r arrays. The two basic approaches for MOVPE growth of HgCdTe, the int erdiffused multilayer process (IMP), and direct alloy growth (DAG) are compared. The paper then focuses on the progress achieved with the IM P approach on lattice-matched CdZnTe substrates. The benefits of the p recursors ethyl iodide (EI) and tris-dimethylaminoarsenic (DMAAs) for controlled iodine donor doping and arsenic acceptor doping at dopant c oncentrations relevant for HgCdTe junction devices are summarized alon g with the electrical and lifetime properties of n-type and p-type HgC dTe films grown with these precursors. The relative merits of the two CdZnTe substrate orientations we have used, the (211)B and the (100) w ith 4 degrees-8 degrees misorientation are compared, and the reasons w hy the (211)B is preferred are discussed. The growth and repeatability results, based on secondary ion mass spectrometry analysis, are repor ted for a series of double-heterojunction p-n-N-P dual-band HgCdTe fil ms far simultaneous detection in the 3-5 mu m and 8-10 mu m wavelength bands. Finally, the device characteristics of MOVPE-IMP in situ grown p-on-n heterojunction detectors operating in the 8-12 mu m band are r eviewed and compared with state-of-the-art liquid phase epitaxial grow n devices.