Citation

Ito Y, Sato M, Wakisaka K, Yoshikado S. IEEJ Trans. Fund. Mater. 2007; 127(8): 452-458+4.

Copyright

(Copyright © 2007, Institute of Electrical Engineers of Japan)

DOI

10.1541/ieejfms.127.452

PMID

unavailable

Abstract

Molybdenum suicide (MoSi2) has high electrical conductivity as much as metal, and high chemical stability than such as SiC in various atmospheres. Therefore, many kinds of MoSi2 bulk-type heaters are practically used for operation up to 1800°C, which is higher than that of SiC heaters. However, MoSi2 is fragile at room temperature and has low creep resistance at high-temperature. The purpose of this study is to fabricate heaters using thin films of MoSi2 deposited on alumina substrates and crucible by RF magnetron sputtering and evaluate their characteristics. MoSi2 thin film was deposited on outside of the alumina crucible without heating substrate and then Pt wire attached using Pt paste by sintering in vacuum. This MoSi2 thin film heaters showed almost linear R-T characteristics and uniform heating state. They also showed good controllability of voltage and stability of power-T characteristics to operate up to 1000°C. However, at 1300°C of heating temperature, heating area of MoSi2 thin film decreased caused by the reaction of Pt and MoSi2 in the case of long-term heating. Thus, Mo thin film was deposited, as a buffer layer, between Pt and MoSi2 thin film to prevent such a reaction. This thin film heater showed good linier R-T characteristics up to 1200°C. But, the temperature coefficient of resistance changed as heating operation was repeated. This is due to the diffusion of Mo atoms into MoSi2. Thus, thin film heater was fabricated with Mo 3Si whose content of Mo is more than that of MoSi2. This heater showed less diffusion of Mo or Pt atoms into thin film and excellent practical characteristics up to 1000°C.

Language: en

Keywords

Thin films; Molybdenum compounds; Molybdenum silicide; Silicides; Electric conductivity; Magnetron sputtering; Alumina substrate; Alumina substrates; Electric heating elements; Improvement of heaters; RF magnetron sputtering; Thin film electric heaters; Thin film high temperature heater