Substrate supporting edge ring with coating for improved soak performance

A substrate support ring, comprising:

• an annular body comprising a ceramic material, the annular body comprising:
• a first sidewall;
• an outer band extending radially outward from the first sidewall, the outer band comprising a film having a first silicon layer, an oxide layer, and a second silicon layer disposed on the oxide layer, the first or second silicon layer selected from the group consisting of amorphous silicon, monocrystalline silicon, and polycrystalline silicon;
• a second sidewall extending from the outer band;
• and
• a substrate supporting region extending radially inward from the first sidewall.

A substrate support ring, comprising:

• an annular body comprising a first material, the annular body comprising:
• a first sidewall;
• an outer band extending radially outward from the first sidewall, the outer band comprising a coating made of a second material that is different than the first material;
• a second sidewall extending from the outer band;
• and
• a substrate supporting region extending radially inward from the first sidewall.