A Thermochemical Process Using Expanding Plasma for Nitriding Thin Molybdenum Films at Low Temperature

Abstract

The mechanical and chemical properties of transition metal nitrides are very attractive for numerous industrial applications. Thin nitride films are expected to be good diffusion barrier in microelectronic devices. Nitrogen diffuses into the whole thickness of the molybdenum film heated at low temperature and exposed to expanding plasma of (Ar-N 2 -H 2 ) compared with pure N 2 plasma. NH x species in the plasma are produced by different homogeneous or heterogeneous reactive mechanisms that results in an expansion of the plasma compared with pure N 2 plasma. NH x species and probably H atoms improve the transfer of nitrogen into the metal by preventing the formation of MoO 2 oxides which act as a barrier of diffusion for nitrogen.

Silicides and Nitrides Formation in Ti Films Coated on Si and Exposed to (Ar-N2-H2) Expanding Plasma

“…The expanding microwave plasma process has been successfully employed to carry out nitriding treatments on thin molybdenum films from 200 nm to 1 µm thick in (Ar-N 2 -H 2 ) plasma [24][25][26]. Nitrogen diffuses in the whole thickness of films even at low temperatures (400 • C).…”

Molybdenum Nitride Films: Crystal Structures, Synthesis, Mechanical, Electrical and Some Other Properties

“…Jauberteau et al [34,[53][54][55] have prepared molybdenum nitride films from Mo films coated on Si (100) substrates in an expanding plasma reactor. The molybdenum coatings have been deposited by electron beam evaporation of a molybdenum target in pure Ar atmosphere at a pressure of 0.5 Pa on Si substrates heated at 673 K with a radiofrequency electrical discharge operating at 50 W. The deposition rates are typically equal to 0.02-0.25 nms…”