Surface Texturing of Silicon by Hydrogen Radicals

The surface texturing method for crystalline Si using hydrogen radicals generated by a tungsten hot filament was developed. We found that tungsten particles supplied from a tungsten filament work as an etching mask against hydrogen radicals. The surface morphology and feature size of the texture structure could be controlled by the particle deposition condition on the Si(100) surface. An inverted pyramid structure was obtained when the particle density was high, suggesting that the etching reaction induced by hydrogen radicals is anisotropic. The reflectance spectra of hydrogen-treated Si surface using this method showed a very low surface reflectance of less than 1% in the range from 200 to 900 nm without any antireflection coatings. The particles on the silicon surface can easily be removed using HF+HNO3 solution. This method is also effective for the texturing of Si(111) wafer, having a potential for the texturing of multicrystalline silicon.