NOVELTY - The method comprises partially arranging an object (10) in a treatment liquid (4), adding a treatment promoting gas to the treatment liquid, introducing the treatment promoting gas with a flow rate of maximum 2-5 liters per minute, via a membrane, into the treatment liquid such that a gas film is formed from the treatment promoting gas at a gas release side of the membrane, and arranging a part of the treatment liquid between the gas film and an area of the object to be treated. The membrane is arranged in a distance of less than 1.5 mm from the area of the object to be treated.    USE - The method is useful for treating an object such as a semiconductor substrate including a silicon solar cell substrate (claimed).    ADVANTAGE - The method allows effective and economical treatment of the object with less effort.    DETAILED DESCRIPTION - The method comprises partially arranging an object (10) in a treatment liquid (4), adding a treatment promoting gas to the treatment liquid with a flow rate of maximum 2-5 liters per minute, via a membrane, into the treatment liquid such that a gas film is formed from the treatment promoting gas at a gas release side of the membrane, and arranging a part of the treatment liquid between the gas film and an area of the object to be treated. The membrane is arranged in a distance of less than 1.5 mm from the area of the object to be treated. The method further comprises: generating the treatment promoting gas by an electrolytic apparatus partially arranged into the treatment liquid and by electrolysis of component of the treatment liquid; and etching the object in the treated area that is greater than the other area of the object introduced into the treatment liquid. The generated gas is partially released in a part of the treatment liquid arranged between the electrolytic apparatus and the area of the object. The treatment liquid is an etching solution consisting of hydrofluoric acid and deionized water. The treatment promoting gas is ozone gas. An emitter doping of a solar cell substrate provided as the object is locally etched back/removed by the etching in the treated area. The emitter doping in other area of the solar cell substrate is etched back by the treatment liquid at the same time strong etching in the treated areas. An INDEPENDENT CLAIM is included for a device for treating an object.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a method for treating an object.    Treatment basin (2)    Treatment liquid (4)    Transport roller (6)    Transport direction (8)    Object. (10)