Regensburg 2002 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 43: Si/Ge
HL 43.1: Vortrag
Freitag, 15. März 2002, 10:30–10:45, H14
Fast time response from Si/SiGe undulating layer superlattices — •Dan Buca1, Stephan Winnerl1, Christoph Buchal1, and Dan-Xia Xu2 — 1Institut für Schichten und Grenzflächen, ISG-IT, Forschungszentrum Jülich — 2National Research Council, Ottawa, Ontario KIA OR6, Canada
We report on vertical metal-semiconductor-metal detectors for infrared radiation with Si-SiGe superlattices as an absorption medium. We have grown Si-Si1−xGex undulating layer superlattices with x = 0.39 and 0.45 by molecular beam epitaxy. In the substrates a single crystalline CoSi2 layer was implanted. It served as the bottom electrode of the vertical detector. Using standard lithography and reactive ion etching, mesa diodes were fabricated using a thin Cr film as a top contact. The detectors showed a quantum efficiency of 5 % for the wavelength 1320 nm and 0.9 % for 1550 nm. We performed temporal response measurements, using a Ti:sapphire laser and an optical parametric oscillator which generates ultrafast pulses at IR wavelengths. An electrical response time of 16 ps (FWHM) was obtained at a wavelength of 1300 nm. The result is compared with a pure Si based vertical metal-semiconductor-metal detector.