We present a comprehensive study on the formation and tuning of the Schottky barrier of NiGeSn metallic alloys on Ge1-xSnx semiconductors. First, the Ni metallization of GeSn is investigated for a wide range of Sn contents (x = 0–0.125). Structural analysis reveals the existence of different poly-crystalline NiGeSn and Ni3(GeSn)5 phases depending on the Sn content. Electrical measurements confirm a low NiGeSn sheet resistance of 12 Ω/□ almost independent of the Sn content. We extracted from Schottky barrier height measurements in NiGeSn/GeSn/NiGeSn metal-semiconductor-metal diodes Schottky barriers for the holes below 0.15 eV. They decrease with the Sn content, thereby confirming NiGeSn as an ideal metal alloy for p-type contacts. Dopant segregation for both p- and n-type dopants is investigated as a technique to effectively modify the Schottky barrier of NiGeSn/GeSn contacts. Secondary ion mass spectroscopy is employed to analyze dopant segregation and reveal its dependence on both the Sn content and biaxial layer strain.

Topics
Semiconductors, Electronic devices, Field effect transistors, Metallization process, Electric measurements, Contact impedance, Schottky barriers, Secondary ion mass spectrometry, Transmission electron microscopy, X-ray diffraction
© 2017 Author(s).
2017
Author(s)
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