TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Method: The formation of the emitter is carried out with a phosphoric acid-containing etching paste, which etches the PSG-layer and the underlying silicon layer in a single processing step. A silicon surface with an increased micro-roughness of an actual texture is obtained by the method. The method comprises treating surface of a silicon wafer with a pyramidal or an amorphous structure with the phosphoric acid-containing etching paste after the texturing of the surface, and thus the increased micro-roughness of the actual texture is obtained. The method comprises: (a) texturing of the surface (with potassium hydroxide/isopropanol or hydrogen fluoride/nitric acid), (b) phosphorus doping ( approximately 35-40 ohm/square diffusion of phosphorus oxychloride), (c) locally etching the PSG and silicon layer, where a conductivity of approximately 80-100 ohm/square is obtained, and cleaning, (d) PSG etching, (e) depositing an anti-reflective coating by plasma enhanced chemical vapor deposition of silicon nitride, (f) screen printing for metallization of the surface at the front side, and subsequently sintering the back side, and (g) insulating an edge; or the step (a), (h) PSG etching at 40 ohm/square diffusion of phosphorus oxychloride, (j) PSG etching, (k) imprinting a Solar etch (RTM: Etching paste) to obtain a resistance of 100 ohm/square, and cleaning with deionized water and/or potassium hydroxide (0.05%), the step (e), the step (f), and the step (g). The method also comprises performing a back side-edge insulation by the etching step.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The paste comprises: phosphoric acid in an amount of 25-80 wt.%; a solvent or a solvent mixture, preferably glycerol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, dimethyl sulfoxide and/or gamma -butyrolactone in an amount of 20-40 wt.%; and at least one non-particulate thickener, preferably polyvinylpyrrolidone and/or hydroxypropyl cellulose, or carbon black and/or low melting wax particles in an amount of 20-35 wt.%. EXAMPLE - Polyvinylpyrrolidone (14 g) was added to the solvent mixture of 85% of phosphoric acid (125 g), diethylene glycol monoethyl ether (75 g) mixed with dimethyl sulfoxide (1:1) under strong stirring. A clear homogeneous mixture was then mixed with carbon black (64 g), and stirred for 2 hours to obtain the etching paste. The obtained paste was provided for etching the PSG layer and the underlying silicon layer to obtain the solar cell.