Abstract
In the beginning of the broad photovoltaic activities all efforts on solar cells were concentrated to develop cheap silicon material and simple production methods. Since about 1980 the insight has come through, that for cost reduction of the total photovoltaic array the efficiency of solar cells plays a considerably more important role. This contribution shows, that relatively simple processes fullfill all requirements for high efficiency silicon solar cells, as there are high diffusion length, good emitter passivation and an effective BSF.