Abstract: The invention relates to a process for the production of silicon and alumina Aluminium is contacted with a molten slag of a calcium oxide and SiO2 under conditions facilitating an aluminothermic reaction, thereby forming silicon and an aluminate slag in two phases which are separated. The aluminate slag is converted to alumina and calcium oxide, which is re-fed in the reaction. The aluminium is provided by melting of aluminium scrap or a combination of different aluminium alloys at a temperature of 700 to 1000° C. The primary aluminium melt is adjusted to a content of 8 to 14% of silicon and then cooled to below 660° C., whereby precipitates are formed, and high purity aluminium is obtained to be introduced into the reaction.

Abstract: A solar cell includes a semiconductor wafer, at least one dielectric layer arranged on the semiconductor wafer, a metal layer arranged on the dielectric layer, and a contact structure arranged in the dielectric layer such that the contact structure provides an electrical connection between the metal layer and the semiconductor wafer. The contact structure has at least one first structure having a minimum dimension and at least one second structure having a maximum dimension, wherein the minimum dimension and the maximum dimension are defined along a surface of the semiconductor wafer and the minimum dimension of the first structure is greater than the maximum dimension of the second structure.

Abstract: A solar cell includes a semiconductor wafer, at least one dielectric layer arranged on the semiconductor wafer, a metal layer arranged on the dielectric layer, and a contact structure arranged in the dielectric layer such that the contact structure provides an electrical connection between the metal layer and the semiconductor wafer. The contact structure has at least one first structure having a minimum dimension and at least one second structure having a maximum dimension, wherein the minimum dimension and the maximum dimension are defined along a surface of the semiconductor wafer and the minimum dimension of the first structure is greater than the maximum dimension of the second structure.