Relation between flow, power, and presence of carrier gas during plasma deposition of thin films

Abstract

Plasma deposition processes have become an integral part of the manufacturing of microelectronic devices. Control of proper deposition parameters and understanding their relation to the composition of the plasma, and therefore to the film properties, is essential for depositing films in a repeatable and a predictable way. Using mass spectrometry, we have studied the influence of input rf power, reactant gas flow, and the presence and concentration of carrier gas on the degree of decomposition of a wide range of starting materials used during plasma deposition. It is shown that all three parameters influence the decomposition of the starting material and therefore the composition and properties of the deposit. It is also shown that different degrees of decomposition for different materials cannot always be predicted from the bonding energy between species being dissociated by a plasma. Using silicon nitride as an example, it is shown that the N/Si atomic ratio in films deposited at various conditions corresponds to the relative degree of decomposition of the reactant gases NH3 and SiH4.