Interfacial reaction between a Ni/Ge bilayer and silicon (100)

• Published in: Journal of applied physics 1990-03, Vol.67 (5), p.2506-2511
• Main Authors: JIAN LI, HONG, Q. Z, MAYER, J. W
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Physics; Solid surfaces and solid-solid interfaces; Surface and interface dynamics and vibrations; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.345502

The sequential formation and dissociation of compounds in the Ni/Ge/Si(100) system have been studied by using Rutherford backscattering spectroscopy, Auger depth profiling, x-ray diffraction, and cross-sectional transmission electron microscopy. Ni2Ge phase is formed first on the Si substrate at 250 °C. A layered structure of NiGe/NiSi/Si(100) is formed after thermal annealing at 350 °C. Upon annealing from 350 to 425 °C, the NiGe phase dissociates, inducing further growth of NiSi phase at the nickel germanide/Si(100) interface. The NiSi phase grows with a (time)1/2 dependence and with an activation energy of 2.1 eV. Marker experiment shows that Ni is a dominant moving species. The dissociation of NiGe lead to an extensive redistribution of Ge and Ni with a configuration of Ge66Si17Ni17/NiSi/Si(100) and this layered structure remains stable until 680 °C. Cross-sectional transmission electron microscopy results show that there are polycrystalline Ge plus a ternary NiSiGe phase on the top layer. High-temperature annealing (>680 °C) induces the inward diffusion of Ge to form a Ge-rich layer on the Si substrate.