An arrangement of linear heat lamps is provided which allows for localized control of temperature nonuniformities in a substrate during semiconductor processing. A reactor includes a substrate holder positioned between a top array and a bottom array of linear heat lamps. At least one lamp of the arrays includes a filament having a varying density and power output along the length of the lamp. In particular, at least one lamp of the arrays includes a filament having a higher filament winding density within a central portion of the lamp relative to peripheral portions of the lamp. In some embodiments, the at least one lamp is a central lamp extending across a central portion of the substrate heated by the lamp. Furthermore, at least one lamp of the arrays has a higher power output within a central portion of the lamp than at peripheral portions of the lamp.