NOVELTY - Etching medium in the form of a paste for printing and optionally doping inorganic glass- or crystalline- layers (based on silica and silicon nitride) on crystalline or amorphous silicon surfaces, comprises at least an etching component, at least a solvent, an inorganic powder in the form of fine-particulate graphite and/or carbon black, at least a fluxing agent, optionally homogeneously dissolved organic thickener, optionally inorganic and/or organic acid and optionally additives such as antifoaming-, thixotropic-, leveling-, degassing- and binding- agent.    USE - The medium is useful in photovoltaic, semiconductor technology, high-performance electronics, mineralogy, glass industry, vision panel for armatures or measuring instruments, glass substrates for outdoor applications, etched glass surfaces for medical-, decorative- and sanitary- applications, filter-, template-, tampon-, stamp-, ink jet- and manual printing- process; for: the production of photodiodes, labels or codes on containers, flat glass, etched glass containers for cosmetics, foods and beverages, glass substrate for solar cells or heat collectors; structuring of glasses for flat screen applications, mineralogical, geological and microstructural investigations; removing silicon oxide and silicon nitride layers doped with silicon oxide; printing and optionally doping inorganic glass- or crystalline- layers (based on silica and silicon nitride) on crystalline or amorphous silicon surfaces; selective opening of passivated layers of silicon oxide and silicon nitride for producing double-level selective emitter and locally p+ baked surface fields in the preparation of semiconductor components and their circuits and elements for high performance electronics (claimed).    ADVANTAGE - The etching medium can be prepared economically.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for an etching technique comprising applying partially or completely the etching medium on the surface of the semi-conductor, optionally activating using energy source and removing the medium after an impact time of 10 second to 15 minutes, preferably 30 seconds t 2 minutes.