NOVELTY - The treatment apparatus (1) comprises a transport device configured to transport objects (8) to the treatment apparatus in a transport direction, a gasifying device (4) by which a treatment gas in a treatment liquid supplied to surface areas of the objects covered in a treatment liquid, and gas retaining elements (9), which are associated with the gasifying device and increase a gas concentration in the liquid in a direction of the objects. The gasifying device is arranged to introduce the treatment gas in the form of gas bubbles to the surface areas of the objects.    USE - The apparatus is useful for treating objects such as flat semiconductor substrates (all claimed) such as silicon solar cell substrates.    ADVANTAGE - The apparatus treats the substrates with reduced gas loss in a rapid, an easy and a controlled manner so that short circuit in the solar cell can be prevented during manufacture.    DETAILED DESCRIPTION - The treatment apparatus (1) comprises a transport device configured to transport objects (8) to the treatment apparatus in a transport direction, a gasifying device (4) by which a treatment gas in a treatment liquid supplied to surface areas of the objects in a treatment liquid, and gas retaining elements (9), which are associated with the gasifying device and increase a gas concentration in the liquid in a direction of the objects. The gasifying device is arranged to introduce the treatment gas in the form of gas bubbles to the surface areas of the objects. The treatment device further comprises discharge openings, and is designed as an etching apparatus. The gas retaining element or a capillary tube (6) is adapted to receive an etching solution consisting of an etching liquid film applied on the object with higher saturation than the gas dissolved in the liquid. The gasifying device comprises a porous membrane through which the treatment gas is supplied to surface areas of the object.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a treatment apparatus.    Treatment apparatus (1)    Gasifying device (4)    Capillary tube (6)    Object (8)    Gas retaining element. (9)