Planar p-on-n HgCdTe heterostructure infrared photodiodes on Si substrates by molecular beam epitaxy

Abstract

We have developed a low temperature procedure for molecular beam epitaxy of CdTe buffer layers on {211} Si wafers and have used Si/ZnTe/CdTe composite substrates for molecular beam epitaxy of double layer Hg1−xCdxTe heterostructures. Planar p-on-n double layer heterostructures were formed by an implantation technique and test diodes were fabricated and characterized. At 77 K, devices with 30×30 μm2 junction area had R0A values in the range 1.5×106–1×107Ω cm2 with a uniform cut-off wavelength of 4.65 μm.

CdZnTe heteroepitaxy on 3″ (112) Si: Interface, surface, and layer characteristics

“…This may be applied to both the Te and As adsorbates and resolved for 0TJ0~ to yield: 0T+ (0Te / VI(Te)/I(Te)sat 1 o-Z = L )+atL I(As) / ~J (5) Here, the first term on the right is nearly one, slightly greater or less depending on whether the Te or As saturated coverage is more complete. By normalizing the measured auger intensities with measured saturation values the relative coverage ratio can be obDhar, Boyd, Martinka, Dinan, Almeida, and Goldsman tained as a function of dose as is shown in Fig.…”

“…In recent years the use of Si based composite substrates to fabricate mid-wavelength (3-5 µm) HgCdTe infrared detectors has been demonstrated. 5,6 However, to fabricate high performance long-wavelength diodes, the crystalline perfection in the Cd l _ XZn.Te buffer layer needs to be improved, and lateral variations in the ZnTe mole fraction must be reduced. The surface morphology must be specular and surface polarity should be of the B-face.…”

Ex Situ Thermal Cycle Annealing of Molecular Beam Epitaxy Grown HgCdTe/Si Layers

“…[1][2][3] However, there remains a problem with defects causing shorter lifetimes and lowering the mobility of minority carriers, and large dark currents in long wavelength infrared (LWIR) detectors. 4,5 Current growth methods of HgCdTe/CdTe/Si result in a dislocation density of mid-to high 10 6 cm À2 , which is relatively high in comparison with the HgCdTe growth on lattice-matched bulk CdZnTe substrates.…”

Molecular beam epitaxy grown long wavelength infrared HgCdTe on Si detector performance

“…1 Silicon wafers offer many advantages due to their low cost, large available sizes, high mechanical strength, industrial maturity, and ability to thermally match the read-out integration chip. [1][2][3][4] Several materialsrelated challenges have, thus far, prevented the realization of this potential. First, the lattice-parameter mismatch between Si and HgCdTe is ϳ19% (a Si ϭ 5.43 Å, a CdTe ϭ 6.48 Å, a HgTe ϭ 6.453 Å).…”