Apparatus for Forming a Conductive Transparent Oxide Film Layer for Use in a Cadmium Telluride Based Thin Film Photovoltaic Device

Abstract

Methods for forming a TCO layer on a substrate are generally provided and include sputtering a TCO layer on a substrate from a target including cadmium stannate. A cap material (e.g., including cadmium) is deposited onto an outer surface of an indirect anneal system, and the TCO layer can be annealed at an anneal temperature while in contact with or within about 10 cm of the cap material. An anneal oven is also generally provided and includes an indirect anneal system defining a deposition surface and an anneal surface such that a cap material deposited on the anneal surface of the indirect anneal system is positioned to be in contact with or within about 10 cm of a thin film on the substrate. A cap material source can be positioned to deposit the cap material onto the deposition surface such that the anneal surface comprises the cap material.

1 . An anneal oven for annealing a thin film layer on a substrate, the anneal oven comprising:
 a transport system configured to carry a substrate through the anneal oven;   a heating element configured to heat the annealing oven to the annealing temperature;   an indirect anneal system defining a deposition surface and an anneal surface, wherein a cap material deposited on the anneal surface of the indirect anneal system is positioned to be in contact with or within about 10 cm of a thin film on the substrate; and,   a cap material source positioned to deposit the cap material onto the deposition surface such that the anneal surface comprises the cap material, wherein the cap material source comprises cadmium.   
     
     
         2 . The anneal oven as in  claim 1 , wherein the indirect anneal system comprises a continuous belt about at least two rollers, wherein the continuous belt defines the deposition surface and the anneal surface. 
     
     
         3 . The anneal oven as in  claim 2 , wherein the conveyor belt has a tension control system configured to adjust the tension in the continuous belt. 
     
     
         4 . The anneal oven as in  claim 3 , wherein the tension control system comprises a plurality of rollers, wherein at least one roller is moveable to adjust the tension in the conveyor belt. 
     
     
         5 . The anneal oven as in  claim 3 , wherein the tension control system comprises a tension roll positioned between a pair of directional rollers, wherein the tension roll is moveable to adjust the tension of the continuous belt. 
     
     
         6 . The anneal oven as in  claim 1 , wherein the indirect anneal system comprises a plurality of slats forming a continuous loop such that the plurality of slats forms a deposition surface and an anneal surface. 
     
     
         7 . The anneal oven as in  claim 6 , wherein the continuous loop of the plurality of slats travels about at least two sprockets, wherein at least one of the sprockets is moveable to adjust the tension of the continuous loop of the plurality of slats.