Thermal management of film deposition processes

A deposition system comprising:

• a vacuum chamber defining an evacuated interior volume;
• a deposition source disposed within the interior volume;
• a substrate holder disposed within the interior volume and arranged to hold a substrate with a first surface of the substrate facing the deposition source and a second surface of the substrate disposed facing away from the deposition source;
• and
• a heat sink having a generally planar member disposed to have a first side of the heat sink in radiative thermal contact with the second surface of the substrate held by the substrate holder, the first side of the heat sink comprising a collection of features in parallel to each other, the features comprising protrusions extending from or recesses extending into the generally planar member, the features having a longitudinal dimension extending toward the second surface and perpendicular to the generally planar member, the features being separated by a lateral dimension parallel to the second surface, wherein the longitudinal dimension is two or more times larger than the lateral dimension between the features, the features thereby dimensioned and aligned to reflect, multiple times in succession, radiative thermal emissions of the second surface of the substrate,
• wherein the generally planar member, the features of the heat sink, and spaces between the features are oriented obliquely relative to the second surface to shield at least some of the features from deposition.