Molecular beam epitaxial growth and performance of integrated two-color HgCdTe detectors operating in the mid-wave infrared band

Abstract

The first report of molecular beam epitaxial growth and performance of HgCdTe two-color detectors for the simultaneous detection of radiation at 4.1 and 4.5 pm is presented. In-situ doped devices with the n-p-n architecture were grown by molecular beam epitaxy on (211)B CdZnTe substrates. Representative structures exhibited x-ray rocking curves with full width at half-maxima of 40-60 arcs. The typical near surface etch pit density in these structures were 4-7 • 106 cm -2. The devices were processed as mesa diodes and electrical contacts were made to the two n-type layers and the p-type layer to facilitate simultaneous operation of the two p-n junctions. The spectral response characteristics of the devices were characterized by sharp turn-on and turn-off for both bands, with R0A values >5 • l0 s ~cm 2 at 77K. The detectors exhibited quantum efficiencies >70% in both bands.

As Doping in (Hg,Cd)Te: An Alternative Point of View

“…When cadmium arsenide (Cd 3 As 2 ) was used as the dopant source, in either MBE [12][13][14][15][16][17] or metalorganic molecular beam epitaxy (MOMBE), 18 the arsenic was active without the need for a hightemperature anneal. In MBE, after a 250°C Hg vacancy-filling anneal, classic p-type conductivity was reported with mobilities of $100 cm 2 V -1 s -1 to 200 cm 2 V -1 s -1 at 77 K and carrier concentrations between 1.6 · 10 16 cm -3 and 2 · 10 18 cm -3 .…”

Progress in MOVPE of HgCdTe for advanced infrared detectors

“…Keywords: HgCdTe, infrared detectors, interdiffused-multilayer-process molecular beam epitaxy (MBE) [1][2][3][4][5][6][7] and metalorganic vapor phase epitaxy (MOVPE). [8][9][10][11][12][13][14] There has been significant progress in MOVPE growth of high quality HgCdTe and in controlled doping with high electrical activation efficiency for both donors and acceptors.…”

MBE growth and characterization of in situ arsenic doped HgCdTe

“…2,4,5 For MBE to achieve all of the potential advantages over other growth methods, a controlled in situ p-type dopant must be developed. 2,4,5 For MBE to achieve all of the potential advantages over other growth methods, a controlled in situ p-type dopant must be developed.…”

“…6 This has led to the focus on column V elements that have much lower diffusion coefficients. 2,8,9 In this approach, in situ p-type doping is achieved in layers after a 250°C Hg-anneal to remove vacancies. Elemental arsenic was initially attempted but incorporation of arsenic into HgCdTe was difficult.…”