TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Method: In the method of manufacturing a solar cell from a silicon wafer, the diffusion source is a dopant containing doping layer, and the dopant containing doping layer is removed by means of an etchant for etching the substance of the dopant containing doping layer preceding the back-etching of the upper layer of the ineffective conductive silicon layer comprised in the dopant containing silicon layer. The removal of the dopant containing doping layer by the etchant for etching the substance of the dopant containing doping layer precedes an oxidation of the surface of the silicon wafer as exposed by the etchant to form a silicon dioxide layer, and subsequently etching of the silicon dioxide layer. A reaction rate of the oxidation reaction is larger than a reaction rate of the dissolution reaction. The first component is a selective agent for oxidation of silicon. The second component is a selective agent for etching silicon dioxide. The oxidation reaction is arranged for forming an oxide top layer which substantially is homogenous and encapsulating. The back-etching is performed to remove the upper layer of the ineffective conductive silicon layer comprised in the phosphor containing silicon layer to a pre-determined thickness. A reaction time for back-etching the upper layer of the ineffective conductive silicon layer comprised in the phosphor containing silicon layer is determined from the reaction rate of the dissolution reaction. The etchant for back-etching is a liquid. The etchant for back-etching is gaseous. The dopant comprises at least one of phosphor, arsenic, and antimony, and the conductive silicon layer is n-type. The diffusion source is a silicate layer comprising at least one of phosphor, arsenic, and antimony as the dopant. The dopant comprises boron, and the conductive silicon layer is p-type. The diffusion source is a silicate layer comprising boron as the dopant. Preferred System: An etching station is disposed between the diffusion furnace and the back-etch etching reactor, the etching station being adapted for removing the dopant containing doping layer by an etchant for etching the substance of the dopant containing doping layer. Along the production track after the etching station an oxidation reactor is disposed for oxidation of the surface of the silicon wafer that is exposed by the etchant in the fetching station, and where after the oxidation reactor a further etching station is disposed for etching of the silicon dioxide layer that is formed in the oxidation reactor. The system comprises a transportation means for transporting the silicon wafer through at least the back-etch etching reactor, a transportation speed of the silicon wafer through at least the back-etch etching reactor being determined from a pre-determined thickness of the upper layer of the ineffective conductive silicon layer comprised in the dopant containing silicon layer that is to be removed. The system comprises a further etching reactor, disposed in the production line after the back-etch etching reactor; the further etching reactor being adapted for removal by a further etchant of a remaining oxide top layer after being exposed to the back-etch etchant. The back-etch etching reactor is an etching bath and the back-etch etchant is an etching liquid. The back-etch etching reactor is a gas reactor system, and the back-etch etchant is gaseous. The further etching reactor is an etching bath and the further etchant is an etching liquid. The further etching reactor is a gas reactor system and the further etchant is gaseous.