Abstract: The present invention relates to multicrystalline p-type silicon wafers with high lifetime. The silicon wafers contain 0.2-2.8 ppma boron and 0.06-2.8 ppma phosphorous and/or arsenic and have been subjected to phosphorous diffusion and phosphorous gettering at a temperature of above 925° C. The invention further relates to a method for production of such multicrystalline silicon wafers and to solar cells comprising such silicon wafers.

Abstract: A printable medium is proposed, such as can be used, for example, during the production of metal contacts for silicon solar cells which are covered with a passivation layer on a surface of a silicon substrate. A corresponding production method and a correspondingly produced solar cell are also disclosed. The printable medium contains at least one medium that etches the passivation layer and metal particles such as nickel particles, for example. By locally applying the printable medium to the passivation layer and subsequent heating, the passivation layer can be opened locally with the aid of the etching medium. As a result, the nickel particles can form a mechanical and electrical contact with the substrate surface, preferably with the formation of a nickel silicide layer. The printable medium and the production method made possible therewith are cost-effective owing to the use of nickel particles, for example, and allow both good electrical contact and avoidance of undesirable high-temperature steps.

Abstract: A method is presented for producing a silicon solar cell with a back-etched emitter preferably with a selective emitter and a corresponding solar cell. According to one aspect, the method comprises the following method steps: producing a two-dimensionally extending emitter at an emitter surface of a solar cell substrate; applying an etching barrier onto first partial zones of the emitter surface; etching the emitter surface in second partial zones of the emitter surface not covered by the etching barrier; removing the etching barrier; and producing metal contacts at the first partial zones. During the method, especially during the etching of the emitter surface in the second partial zones, a porous silicon layer is advantageously produced, which is then oxidized. This oxidized porous silicon layer can subsequently be etched away together with any phosphorus glass that may be present.

Abstract: A method is presented for producing a silicon solar cell with a back-etched emitter preferably with a selective emitter and a corresponding solar cell. According to one aspect, the method comprises the following method steps: producing a two-dimensionally extending emitter at an emitter surface of a solar cell substrate; applying an etching barrier onto first partial zones of the emitter surface; etching the emitter surface in second partial zones of the emitter surface not covered by the etching barrier; removing the etching barrier; and producing metal contacts at the first partial zones. During the method, especially during the etching of the emitter surface in the second partial zones, a porous silicon layer is advantageously produced, which is then oxidised. This oxidised porous silicon layer can subsequently be etched away together with any phosphorus glass that may be present.

Abstract: The present invention relates to multicrystalline p-type silicon wafers with high lifetime. The silicon wafers contain 0.2-2.8 ppma boron and 0.06-2.8 ppma phosphorous and/or arsenic and have been subjected to phosphorous diffusion and phosphorous gettering at a temperature of above 925° C. The invention further relates to a method for production of such multicrystalline silicon wafers and to solar cells comprising such silicon wafers.

Abstract: The invention relates to an electrophoretic dipping system comprising at least one bowl (1) which can be filled with a liquid and an object which is to be coated and which can be dipped therein. At least one power supply unit (5A, 5B, 5C) produces DC voltage with definite residual ripple from AC voltage. The one pole thereof can be connected to at least one electrode of a first polarity (3A, 3B, 3C), said electrode being arranged in the dipping bowl (1) and the other pole thereof can be connected to the object which is to be coated. The power supply unit (5A, 5B, 5C) comprises one uncontrolled diode rectifler bridge (19) and an IGBT switch (22) which comprises a controllable oscillator (24) and a power transistor (23). The controllable oscillator (24) generates pulses having a repetition frequency ranging from between 5 and 30 kHz with variable pulse widths. The power transistor (23) is controlled by said pulses.