An overview of plasma sources suitable for dry etching of solar cells

The characteristic feature of a plasma system is the method of plasma excitation. A parallel plate system, i.e. reactive ion etching (RIE), an atmospheric downstream plasma (ADP) source and two types of microwave plasma sources (slot and linear antenna) are tested regarding their suitability for solar cell processing in terms of high throughput and plasma-induced damage. Possible damage in silicon etching is analysed by means of solar cells. Although damage can be minimized in RIE, a decrease of cell parameters can only be avoided completely if ion bombardment is avoided (slot and linear antenna plasma source, ADP). The parallel plate system and the slot antenna source show insufficient etch rates (<1 μm/min) while those of linear antennas and ADP are extremely high (>10 μm/min). Therefore, of the analysed plasma sources, the latter represent the most promising systems for solar cell processing