Title :
Oxidation-Induced Growth of Sn Whiskers in a Pure Oxygen Gas Environment
Author :
Crandall, E.R. ; Flowers, G.T. ; Dean, R.N. ; Bozack, M.J.
Author_Institution :
Center for Adv. Vehicle & Extreme Environ. Electron. (CAVE3), Auburn Univ., Auburn, AL, USA
Abstract :
Several studies have demonstrated that tin (Sn) whisker growth is enhanced by exposure to atmospheric and high relative humidity conditions. The presumption is that diffusion of oxygen into the Sn thin film results in the lattice expansion of metal oxide phases which place the film under compressive stress. The increased stress is subsequently relieved in part by growth of Sn whiskers. In order to clarify the role of oxygen on whisker production, we exposed sputtered thin films (~ 1400 A) of Sn on brass to a high pressure (1 atm) of pure 99.999% oxygen in a highly controlled, high vacuum environment. A dramatic increase (~ 9X, ~ 16x103 whiskers/cm2) in whisker growth occurred for the pure 02 exposed samples compared to similar ambient room temperature/humidity incubated samples. X-ray photoelectron spectroscopy (XPS) analysis of the resultant oxidized surface showed that the pure O2 exposed samples contained a higher fraction of SnO/SnO2 compared to atmospheric-exposed Sn on brass.
Keywords :
X-ray photoelectron spectra; compressive testing; photoelectron spectroscopy; tin; whiskers (crystal); Sn; X-ray photoelectron spectroscopy analysis; compressive stress; lattice expansion; oxidation-induced growth; pure oxygen gas environment; whiskers; Films; Humidity; Sputtering; Substrates; Surface morphology; Tin;
Conference_Titel :
Electrical Contacts (HOLM), 2010 Proceedings of the 56th IEEE Holm Conference on
Conference_Location :
Charleston, SC
Print_ISBN :
978-1-4244-8174-3
DOI :
10.1109/HOLM.2010.5619454