Remote plasma reactors are being developed for treating surfaces between layers in MOS (metal-oxide-semiconductor) stacks, and for depositing (or growing) the SiO2 layer. Systemmatic differences in the properties of oxide layers produced in remote plasma reactors have been observed when using different source gases for the oxygen precursors, presumably resulting from variations in the deposition precursors.
In remote plasma enhanced chemical vapor deposition (RPECVD) of SiO2, it has been found that the fluxes of SiH2O, SiH3, and SiHn, directly scale in the same manner as the experimental precursor rates. The production and uniformity of these precursors largely depends on the rate of oxidation of SiH4. Reactions of O(3P) with SiH4 proceed by a series of H abstraction and elimination reactions. Since the fluxes of O(3P) atoms are large , and not rate limiting, this scaling supports the proposal that the surface catalyzed reactions between atomic/molecular oxygen and SiHn are deposition precursors. To investigate the reaction pathways and to identify depostion precursors, a model has been developed to simulate production and transport of such precusors.
Figure 1 Schematic of RPECVD tool used for deposition.
Figure 4 Neutral fluxes to the wafer.
Figure 5 Design of experiment results for flux of atomic Oxygen.