Wafer susceptor with improved thermal characteristics

A device comprising:

• a base portion having a substantially circular first surface and a cylindrical surface extending from the first surface;
• and
• a ring portion disposed within the base portion and having a contact surface defined thereupon,
• wherein the contact surface is configured to contact an edge of a substrate without the device contacting any surface of the substrate extending from the edge.

A substrate-retaining device comprising:

• a non-linear first surface having a perimeter defined thereupon;
• a plurality of contact regions disposed at the perimeter;
• and
• a plurality of noncontact regions disposed at the perimeter and interspersed with the plurality of contact regions,
• wherein the first surface within each of the noncontact regions extends past the first surface within each of the contact regions, and
• wherein each of the contact regions includes a contact surface configured to contact an edge of a retained substrate without the substrate-retaining device contacting a circumferential surface of the retained substrate extending from the edge.