Abstract: A process for the production of photoresist relief structures possessing an overhang character comprising coating a substrate with a positive-working photoresist composition based on phenol/formaldehyde condensates of the novolak resin type and photosensitive o-quinonediazide compounds, imagewise overexposure of the photoresist layer at an energy exceeding that required to produce relief structures with a 90.degree. angle between the photoresist compound and the substrate, and treatment of the overexposed layer and substrate with a buffered, aqueous, alkaline developer containing 1-100 ppm of an oxyethylated alkylphenol as a non-ionic surfactant.

Abstract: On a substrate (1) covered with a chromium layer (2), a positive resist layer (3) is applied, exposed through an exposure mask with the mask pattern corresponding to the negative of the respective chromium pattern, developed, and blanket-coated with a less than or equal to 10 nm thick layer (4) of silicon dioxide. Then photoresist layer (3) and the silicon layer (4) thereon are lifted off, and finally the chromium layer (2) is dry-etched, the remaining silicon dioxide layer (4) being used as an etch mask.Chromium masks are used e.g. in the production of semiconductor circuits. By means of the reverse process, structures whose smallest dimensions are in the micrometer and the submicrometer range can be transferred into chromium layers with sharp edges.

Abstract: A method for doping silicon bodies by the diffusion of boron into the bodies is described. The method is an improvement of processes where the silicon bodies are exposed in a first heating process to a gas mixture containing a predetermined boron quantity and boron and oxygen in a predetermined quantitative ratio and a second heating process is used to drive the boron into the silicon. In the method, a borosilicate glass layer and a boron-rich silicon dioxide layer are removed by first immersing the silicon body in hydrofluoric acid diluted with water and subsequently in an aqueous sulfuric acid/potassium permanganate solution.

Abstract: An open diffusion method of doping a silicon body with boron. In a first open diffusion heating step, a boron glass is deposited upon the silicon body with a silicon-rich boron phase (SiB.sub.6) formed beneath the glass where deposition is directly on silicon. The boron glass and SiB.sub.6 layer are formed by exposing the silicon body to a gas mixture containing a predetermined boron quantity and boron and oxygen in a predetermined quantitative ratio. Etching steps then permit the removal of the boron glass without deleteriously affecting the SiB.sub.6 layer or underlying silicon, or uncontrollably affecting any SiO.sub.2 masking layers. In a second heating step, at least a part of the boron from the SiB.sub.6 layer is driven into the silicon in an inert or oxidizing atmosphere.

Abstract: A method of making silicon solar cells and other silicon photovoltaic cells. The method includes the steps of forming a silicon element having a metallic electrode coating on one surface of the element, applying to the other surface of the element a coating containing aluminum and silicon and heating the coated element at a temperature below the eutectic temperature of aluminum-silicon to form an antireflective coating of a fine matrix of silicon pyramids doped with aluminum. The matrix formed on the surface of the silicon has an overlying aluminum coating. A portion of the aluminum coating is removed to expose the matrix for use as a photovoltaic cell.

Abstract: A process for manufacturing Phosphorus-doped surface layers in semiconductor substrates. The surface of the substrate is wetted with hot phosphoric acid and then coated prior to diffusion with a layer of material which is stable at the diffusion temperature.