Advances in composition control for 16 µm LPE P-on-n HgCdTe heterojunction photodiodes for remote sensing applications at 60K

Abstract

With good composition control in both p-type cap and n-type base LPE layers, it is possible to make barrier-free two-layer P-on-n HgCdTe heterojunction photodiodes with very long cutoff wavelengths. Diode arrays with good R o A operability, good quantum efficiency, and low 1/f noise at 60K have been demonstrated at cutoff wavelengths to 16.3 µm. The diode performance continues to improve at lower temperatures, following a diffusion-current trend to at least 35K. Measured R o A values of 2 × 10 5 ohm-cm 2 for an 18 µm cutoff at 35K are the highest reported at this very long wavelength. A simple defect model applied to the area dependence of R o A at 40K implied a defect areal density of 3 × 10 4 cm -2 and a defect impedance of 3 × 10 6 ohm.

MBE HgCdTe Technology: A Very General Solution to IR Detection, Described by “Rule 07”, a Very Convenient Heuristic

“…Over the 13 orders of magnitude covered, the largest deviation of data from the model is <6% of the exponent or a factor of 0.4 to 2.5 times. Figure 3 shows the same model and TIS data with HgCdTe data from other laboratories [8][9][10][11] superposed, as well as representative data from both InSb 12 ($5.3 lm) and lattice-matched InGaAs 13 ($1.7 lm). It is easy to see that HgCdTe is only slightly worse (3· to 10· depending on temperature) than optimal InGaAs, and many orders of magnitude better than InSb.…”

Realization of very long wavelength infrared photovoltaic detector arrays on mercury cadmium telluride epitaxial layers grown on Si substrates

“…22 Discussions in the preceding paragraph have, however, brought out yet another equally plausible explanation for the improvement of R 0 A in low carrier concentration samples.…”

Performance of molecular-beam epitaxy-grown midwave infrared HgCdTe detectors on four-inch Si substrates and the impact of defects

“…12,13 Concentrating on the 40 m unit cell FPAs (the bulk of the existing data), the majority of the operability values correspond to the 0-500 cm −2 defect-density range. In this study, we found consistent results within the various groups of diodes.…”