Combined Ozone/HF/HCI Based Cleaning and Adjusted Emitter Etch-Back for Silicon Solar Cells

RCA cleaning in multiple variations is widely used in photovoltaic production lines for high efficiency solar cells. These commonly peroxide based cleaning procedures are effective, but suffering from large chemical consumption and waste generation. A substitution of hydrogen peroxide by ozone in cleaning solutions is not realized yet for PV devices despite its high oxidation potential and facility advantages. The very high potential of ozone cleaning has been shown in various microelectronic applications [1-7]. Dissolved ozone in HF/HCl solution gives the option of cleaning by combined silicon etching and oxidizing as well as complexing metal contaminations due to F - and Cl - .