VERTICAL PIN PHOTODIODES BASED ON GE/SI HETEROSTRUCTURES GROWN BY MOLECULAR BEAM EPITAXY
I.B. Chistokhin1, K.B. Fritzler1, M.S. Aksenov1, A.S. Deryabin1, L.V. Sokolov1, I.D. Loshkarev1, A.V. Kolesnikov1, A.I. Nikiforov1, V.Yu. Abrosimov2
1Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
2Zelenograd nanotechnology center” JSC, Zelenograd, Russia
Keywords: PIN mesa-photodiode, Ge/Si heterostructures, planar processing
Abstract
Vertical PIN mesa-photodetectors in the wavelength range 1310-1550 nm based on Ge/Si heterostructures have been fabricated and characterized.The undoped and doped Ge layers were grown by molecular beam epitaxy on Si(100) highly doped p-type substrates. The level of Sb doping in the n+ region and the Si diffusion profile in Ge were determined by secondary ion mass spectrometry. The threading dislocation density was reduced to 2·107 cm-2 due to the implementation of a two-stage growth process for Ge followed by thermal annealing. According to X-ray diffractometry data, the residual tensile deformation of the Ge epitaxial layer on a silicon substrate after annealing was +0.11%. At a reverse bias of 1-2 V, the photodetectors showed high sensitivity at a wavelength of 1310 nm (0.5 A/W with a thickness of 1.5 µm) with a moderate dark current density (1-2×10-2 A/cm2). These results are promising for the efficient development of photonic integrated circuits on silicon.
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