Low-temperature reduction of SnO2 by floating wire-assisted medium-pressure H2/Ar plasma

Reduction of SnO2 to form spherical Sn particles and Sn etching are obtained by floating wire (FW)-assisted medium-pressure H-2/Ar plasma. High-density H-2/Ar plasma (10(14) cm(-3)) with a larger treatment area at medium pressure (10 kPa) produces a two-times higher removal rate of SnO2 (0.111 mg/min) than that at atmospheric pressure with the same treatment area of 300 mm(2). SnO2 film is removed from the glass surface by a two-step process involving (1) reduction of SnO2 by FW-H-2/Ar plasma to form spherical Sn particles and (2) removal of low-contact Sn particles by water-based cleaning. High surface smoothness (roughness of 0.488 nm) and high optical transmittance (>92%) of treated samples indicate no damage compared to that of pristine quartz glass.