NOVELTY - Doper assembly comprises: (a) a hot acid vapor generation chamber (36a), including an atomizer and means for heating the vapor; (b) a continuous conveyor system for transport of cool silicon wafers; (c) a vapor application process chamber; (d) the vapor generation chamber; (e) the vapor process chamber confining and directing a layer of the acid vapor onto the wafer surface to form a condensation layer of acid on it; and (f) means for drying the wafers after formation of an acid vapor condensation layer on the wafer surface.    USE - The doper assembly is useful for applying a doping composition to at least one surface of a silicon wafer for subsequent firing to form an p-n junction or back contact layer for solar cells (claimed).    ADVANTAGE - The doper assembly: provides the wafers with excellent sheet resistance; eliminates the need for consumable single-use paper transport substrates, and shortens the time required for the dopant application stage portion of the overall solar cell wafer production cycle; and provides the doping of the surface layer of solar cell silicon wafers with uniformity of thickness of the dopant composition, orthogonally across the wafer surface, in the wafer to wafer consistency and in the increased throughput to match the downstream diffusion furnaces on a small footprint.    DETAILED DESCRIPTION - Doper assembly comprises: (a) a hot acid vapor generation chamber (36a) 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 the vapor; (b) a continuous conveyor system for transport of cool silicon wafers in a generally horizontal path; (c) a vapor application process chamber having an entry and an exit for the conveyor to transport the wafers through the process chamber, where the wafers is oriented during transport with a surface to which the dopant acid composition is to be applied facing upwardly; (d) the vapor generation chamber is disposed in communication with the vapor application process chamber to pass the hot concentrated acid vapor into the application process chamber; (e) the vapor process chamber confining and directing a layer of the acid vapor onto the wafer surface to form a condensation layer of acid on it; and (f) means for drying the wafers after formation of an acid vapor condensation layer on the wafer surface to produce doped wafers. INDEPENDENT CLAIMS are also included for:    (1) processing silicon wafers having deposited on a dopant composition for firing in a diffusion furnace to form an p-n or back contact layer for solar cells, comprising: atomizing a concentrated liquid acid composition with compressed gas and heating the atomized liquid to form a hot concentrated acid vapor; continuously transporting cool silicon wafers through a concentrated acid vapor application process zone; directing the hot concentrated acid vapor into contact with the cool silicon wafers having a surface to which the concentrated acid vapor is to be applied facing upwardly as they are transported through the vapor application process zone to condense liquid concentrated acid onto the wafer surface; and drying the condensed concentrated acid on the wafer surface to form doped wafers for subsequent firing in the diffusion furnace to form the p-n junction or back contact layer;    (2) a doper UV pre-treatment assembly to feed silicon wafers to the doper assembly, where the UV pre-treatment assembly comprising a wafer transport assembly, a UV chamber in which UV lamps (34) are disposed above the wafer transport assembly, and the UV lamps are oriented to expose a wafer surface to be doped to UV radiation as the wafers are transported through the chamber; and    (3) a doper UV treatment assembly to feed doped wafers to a diffusion furnace, where the UV treatment assembly comprises a doped wafer post-treatment chamber having at least one UV lamp disposed for UV radiation conditioning of the doped surface of wafers prior to diffusion firing.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-sectional view of the dopant module.    Doper module (12a)    Wafer processing chamber (28)    Lamps (34)    Vapor generation chamber (36a)    Lifter (44)