NOVELTY - Aqueous alkaline etching and cleaning composition (A) comprises: at least one quaternary ammonium hydroxide; and at least one component comprising water-soluble sulfonic acid compounds (I), water-soluble phosphonic acid compounds (II), water-soluble sulfuric acid ester compounds (III), water-soluble phosphoric acid ester compounds (IV) or water-soluble phosphoric acid ester compounds (V), and their water-soluble salts.    USE - (A) is useful for the treatment of silicon substrates, preferably silicon wafers, which are used for manufacturing devices generating electricity upon exposure to electromagnetic radiation, where the devices are photovoltaic cells and solar cells (preferably selective emitter solar cells, metal wrap through solar cells or emitter wrap through solar cells), and the electromagnetic radiation is solar radiation. (A) is useful for the modification of the surface of the silicon substrates by etching and oxidation, the removal of phosphorus silicate glass and dead layers generated by the phosphorus emitter doping, the removal of porous silicon generated by the wet edge isolation and/or the removal of debris which has re-contaminated the surface of the silicon substrates (all claimed).    ADVANTAGE - (A) avoids the formation of haze and the re-contamination of the surface of the silicon substrates. (A) has strong hydrophilizing effect so that the resulting hydrophilic surface could be exceptionally well wetted with highly polar spray-on phosphorus emitter sources such as aqueous or alcoholic phosphoric acid so that the doping and the formation of the emitters could be controlled precisely. The method provides the device having high efficiencies and a uniform appearance in high yields. (A) is excellently suited as wet cleaning and modification compositions in the additional wet cleaning and modification step carried out after the phosphorus silicate glass removal.    DETAILED DESCRIPTION - Aqueous alkaline etching and cleaning composition (A) comprises: at least one quaternary ammonium hydroxide; and at least one component comprising water-soluble sulfonic acid compounds of formula ((R1-SO3-)nX(n+)) (I), water-soluble phosphonic acid compounds of formula (R-PO32-(X(n+))3-n) (II), water-soluble sulfuric acid ester compounds of formula ((RO-SO3-)nX(n+)) (III), water-soluble phosphoric acid ester compounds of formula (RO-PO32-(X(n+))3-n) (IV) or water-soluble phosphoric acid ester compounds of formula (((RO)2PO2-)-n X(n+)) (V), and their water-soluble salts.    X = H, alkaline metal and alkaline-earth metal;    R1 = 2-5C aliphatic moieties or 4-6C cycloaliphatic moieties (both having at least one olefinically unsaturated double bond);    R = 2-5C aliphatic moieties or 4-6C cycloaliphatic moieties (both having at least one olefinically unsaturated double bond), or alkylaryl, where the aryl is benzene or naphthalene, the alkyl moieties are methylene, ethane-diyl or propane-diyl, and the phosphorus atom in (II) is bonded directly and the sulfur atom in (III) and the phosphorus atom in (IV) and (V) are each bonded via an oxygen atom to an aliphatic carbon atom; and    n = 1 or 2.    INDEPENDENT CLAIMS are included for:    (1) treating the surface of a silicon substrate comprising providing (A), contacting at least one major surface of the silicon substrate at least once with (A) to obtain a clean hydrophilic surface and removing the major surface from the contact with (A); and    (2) manufacturing devices generating electricity upon the exposure to electromagnetic radiation comprising (a) texturing at least one major surface of a silicon substrate with an etching composition, hence generating a hydrophobic surface, (b) hydrophilizing the hydrophobic surface by employing the method for treating the surface of the silicon substrate, (c) applying at least one spray-on phosphorus emitter source onto the hydrophilic surface, (d) heating the silicon substrate contacted with the emitter source, hence forming phosphorus emitters within the silicon substrate or phosphorus emitters within the silicon substrate and a phosphorus silicate glass on top of the surface of the silicon substrate, (e) modifying the upper layer of the silicon substrate containing the phosphorus emitters or removing the phosphorus silicate glass from the surface of the silicon semiconductor and, then modifying the upper layer of the silicon substrate containing the phosphorus emitters, (f) depositing an antireflective layer on top of the modified upper layer of the silicon substrate containing the phosphorus emitters, hence obtaining an intermediate, and (g) further processing the intermediate to obtain the device; or the step (a) as above per se, treating the hydrophobic surface of the silicon substrate in a heated atmosphere containing at least one gaseous phosphorus emitter source, hence forming phosphorus emitters within the silicon substrate or phosphorus emitters within the silicon substrate and a phosphorus silicate glass on top of the surface of the silicon substrate, followed by carrying out the step (e) by the method for treating the surface of silicon substrate, and the steps (f) and (g).