A wafer carrier (32) used in wafer treatments such as chemical vapor deposition has pockets (40) for holding the wafers (70) and support surfaces (56) for supporting the wafers above the floors (46) of the pockets. The carrier (32) is provided with thermal control features such as trenches (41) which form thermal barriers having lower thermal conductivity than surrounding portions of the carrier. These thermal control features promote a more uniform temperature distribution across the wafer surfaces (72, 74) and across the carrier top surface (34).
