Abstract: The embodiments relate to a method for producing a solar cell having a rear-side contact with a tunnel barrier. A monocrystalline wafer having a front side and a rear side may be provided with silicon and a dopant. A tunnel barrier is produced on the wafer, and a polycrystalline or amorphous layer is deposited on the tunnel barrier. The polycrystalline or amorphous layer includes silicon and a dopant. The polycrystalline or amorphous layer is removed on the front side by gas-phase etching.

Abstract: A liquid agent for the surface treatment of monocrystalline wafers, which contains an alkaline etching agent and also at least one low-volatile organic compound. Systems of this type can be used both for the cleaning, damage etch and texturing of wafer surfaces in a single etching step and exclusively for the texturing of silicon wafers with different surface quality, whether it now be wire-sawn wafers with high surface damage or chemically polished surfaces with minimum damage density.

Abstract: A method for local contacting and local doping of a semiconductor layer including the following process steps: A) Generation of a layer structure on the semiconductor layer through i) application of at least one intermediate layer on one side of the semiconductor layer, and ii) application of at least one metal layer onto the intermediate layer last applied in step i), wherein the metal layer at least partly covers the last applied intermediate layer, B) Local heating of the layer structure in such a manner that in a local region a short-time melt-mixture of at least partial regions of at least the layers: metal layer, intermediate layer and semiconductor layer, forms. After solidification of the melt-mixture, a contacting is created between metal layer and semiconductor layer. It is essential that in step A) i) at least one intermediate layer designed as dopant layer is applied, which contains a dopant wherein the dopant has a greater solubility in the semiconductor layer than the metal of the metal layer.

Abstract: A method for producing a solar cell from a silicon wafer, including the following process steps: A) texturizing one side of the silicon substrate (1) for improving the absorption or removing saw damage on one side of the silicon substrate (1); B) generating an emitter area (2) on one side of the silicon substrate (1) by diffusing in a doping material for forming a pn transition; C) removing a glass layer which comprises the doping material; D) applying a masking layer (3) which is a dielectric layer; E) removing one part of the material of the silicon substrate (1); F) applying metal structures (5, 6) for electrically contacting the solar cell. It is significant that thermal oxidation is performed between the process steps E and F for forming an oxide layer (4) and that the masking layer (3) and the oxide layer (4) remain on the silicon substrate (1) in the subsequent process steps.

Abstract: A method for local contacting and local doping of a semiconductor layer including the following process steps: A) Generation of a layer structure on the semiconductor layer through i) application of at least one intermediate layer on one side of the semiconductor layer, and ii) application of at least one metal layer onto the intermediate layer last applied in step i), wherein the metal layer at least partly covers the last applied intermediate layer, B) Local heating of the layer structure in such a manner that in a local region a short-time melt-mixture of at least partial regions of at least the layers: metal layer, intermediate layer and semiconductor layer, forms. After solidification of the melt-mixture, a contacting is created between metal layer and semiconductor layer. It is essential that in step A) i) at least one intermediate layer designed as dopant layer is applied, which contains a dopant wherein the dopant has a greater solubility in the semiconductor layer than the metal of the metal layer.

Abstract: A liquid agent for the surface treatment of monocrystalline wafers, which contains an alkaline etching agent and also at least one low-volatile organic compound. Systems of this type can be used both for the cleaning, damage etch and texturing of wafer surfaces in a single etching step and exclusively for the texturing of silicon wafers with different surface quality, whether it now be wire-sawn wafers with high surface damage or chemically polished surfaces with minimum damage density.

Abstract: The invention relates to a method for simultaneous doping and oxidizing semiconductor substrates and also to doped and oxidized semiconductors substrates produced in this manner. Furthermore, the invention relates to the use of this method for producing solar cells.