Wettability and reactivity of molten silicon with various substrates

• Published in: Applied physics. A, Materials science & processing Materials science & processing, 2004-03, Vol.78 (4), p.617-622
• Main Authors: YUAN, Z, HUANG, W. L, MUKAI, K
• Format: Article
• Language: English
• Subjects: Boron nitride; Condensed matter: structure, mechanical and thermal properties; Contact; Contact angle; Exact sciences and technology; Forsterite; Physics; Silicon; Silicon carbide; Silicon nitride; Silicon substrates; Solid-fluid interfaces; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Wetting
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-002-2001-8

Contact angles of molten silicon on various substrates have been determined using the sessile drop method and reactivity has been investigated by examining cross sections between silicon and substrates with an electron-probe microanalyzer (EPMA). The contact angles between molten silicon and oxide substrates, such as SiO2(s), Al2O3(s) and MgO(s), are in the range 85 to 88. The reaction zone is composed of forsterite (2MgO.SiO2) and clinoenstatite (2MgO.2SiO2) on the MgO(s)-side of the interface between the Si and MgO. The contact angle between molten silicon and Si3N4 is about 90. Molten silicon spreads over the SiC plate and the contact angle is estimated to be 8. Large contact-angle values (around 145) have been observed on BN substrates. At the interface between Si(l) and the BN substrate, a discontinuous Si3N4 layer is believed to form and might retard the dissolution of BN into molten silicon. The BN substrate is regarded as being the most suitable substrate for supporting a molten silicon drop during surface tension measurements, due to the large contact angle and low contamination.