Patent ID: 8742532

Claim:
A doper assembly for applying a doping composition to at least one surface of a Silicon solar cell wafer for subsequent firing to form an p-n junction or back contact layer, comprising in operative combination: a. a hot phosphoric or boric acid vapor generation chamber, including: i. an atomizer for atomizing highly concentrated liquid dopant acid composition with gas under pressure to create a highly concentrated acid vapor, and ii. means for heating said vapor; b. a continuous conveyor system for transport of cool silicon wafers in a generally horizontal path, said continuous conveyor system includes multiple lanes arrayed side-by-side, each lane having its own at least one transport belt, said belts of all zones being driven in synchrony by a common drive system; c. a vapor application process chamber having an entry and an exit for said conveyor to transport said wafers through said process chamber, said wafers being oriented during transport with a surface to which said dopant acid composition is to be applied facing upwardly; d. said vapor generation chamber is disposed in communication with said vapor application process chamber to pass said hot concentrated acid vapor into said application process chamber; e. said vapor process chamber confining and directing a layer of said acid vapor onto said wafer surface to form a condensation layer of acid thereon; and f. means for drying said wafers during transport in said horizontal path after formation of an acid vapor condensation layer on said wafer surface to produce doped wafers.