Perfect adsorption of PPB-level surfactant in 5% KOH water solution on a silicon surface changing anisotropic etching properties

This paper reports the effect of ppb-level non-ionic surfactant, Triton-X-100, on the etching of Si {100} and Si {110} plane in 5wt% KOH solution. Si {100} and Si {110} etching rates decreased dramatically when 10 ppb of Triton was added to 5wt% KOH solution. In pure 5wt% KOH solution, micro-pyramids appear on the Si {100} etched surface and long zigzag shapes dominate Si {110} surface morphologies. However, in 5wt% KOH with addition of ppb-level of Triton, the etched surface becomes mirror-like. This result shows that a ppb-level of Triton is adsorbed perfectly on the silicon surface during etching.