Silicon nitride deposition using N2-rare gas radio-frequency afterglows

Summary form only given. Remote plasma chemical vapor deposition (RPCVD) is being used to form silicon nitride films. In the RPCVD process, high-energy ions and electrons do not come into contact with the silane reactant. Previous researchers have indicated that this is important for the formation of low-hydrogen-content silicon nitride films and is the key difference between remote plasma deposition and immersion plasma deposition. Experiments have been coordinated with theoretical modeling so that experimental parameters can be chosen to promote the formation of Si₃N₄ precursors selectively. The model of the He-N₂ discharge and afterglow includes the first two He metastables, a lumped He^* state, He ⁺, and dimer metastables and ions. An important but uncertain rate is that for dissociation by V-V energy pooling, which depends on the vibrational manifold population. A rate for this process has been extracted from comparison of the model with published measurements of N and N₂(A) production in pure N₂ discharges. Ar-N₂ mixtures are of special interest because Ar(³P₂) and Ar(³P₀) efficiently and selectively excite N₂(A). It is shown that the Ar metastables that arrive in the deposition region are created not in the discharge, but in the afterglow via recombination of dimer ions