Black-silicon production process by CF4/H2 plasma

Nanoscale structures in silicon have been produced by means of a maskless plasma process that employs tetrafluoromethane and hydrogen. The influence of the radio-frequency power and process time on the surface texturing was studied. Desirable texturing effect has been achieved by applying an RF power in the range of 200-280 W and process time in the range of 20-30 min. The textured surface is characterized by nanopillars with lateral dimensions ranging from50 to 300 nm and with a depth in the 100-300 nm range. Depending on process parameters in the plasma etching recipe, the optical reflectance of the silicon surface is lowered and R < 5% is reached in the range going from the visible to the near-IR region.