A self-centering susceptor ring assembly is provided. The susceptor ring assembly includes a susceptor ring support member and a susceptor ring supported on the susceptor ring support member. The susceptor ring support member includes at least three pins extending upwardly relative to the lower inner surface of the reaction chamber. The susceptor ring includes at least three detents formed in a bottom surface to receive the pins from the susceptor ring support member. The detents are configured to allow the pins to slide therewithin while the susceptor ring thermally expands and contracts, wherein the detents are sized and shaped such that as the susceptor ring thermally expands and contracts the gap between the susceptor ring and the susceptor located within the aperture of the susceptor ring remains substantially uniform about the entire circumference of the susceptor, and thereby maintains the same center axis.