Abstract: A deposition chamber for use in depositing vapors on substrates. The deposition chamber comprises a hollow outer containment vessel which defines a first longitudinal axis. Rotatably mounted within the containment vessel is a tumbler having first and second ends and an interior compartment for accommodating the substrates. The tumbler defines a second longitudinal axis which is angularly off-set relative to the first longitudinal axis. Disposed within the tumbler are vapor inlet and outlet ports, both of which communicate with the interior compartment. The rotation of the tumbler facilitates the reciprocal movement of substrates positioned within the interior compartment between the first and second ends of the tumbler.