Edge ring for a thermal processing chamber

An edge ring for supporting a substrate in a processing chamber, comprising:

• a ring shaped body defined by an inner edge, an outer edge, an upper side and a lower side, wherein the inner edge and outer edge are concentric about a central axis;
• a lip extending radially inward from the inner edge of the ring shaped body, wherein the upper surface of the lip is below an upper surface of the ring shaped body so that the lip and body form a recess for holding the substrate and at least a portion of an upper surface of the lip is configured to support a substrate around an outer edge of the substrate so that the substrate is substantially parallel to a major plane that is perpendicular to the central axis;
• and
• one or more surface area increasing structures extending from at least one of the upper side or lower side of the ring shaped body, wherein the one or more surface area increasing structures comprises a fin extending from the lower side of the ring shaped body, the fin forms a circular wall concentric to the inner edge and the outer edge, the fin is positioned between the inner edge and the outer edge, the fin is disposed at the inner edge of the ring shaped body, and the lip extends from the fin.