Si (100) and (110) etching properties in 5, 15, 30 and 48 wt%KOH aqueous solution containing Triton-X-100

Abstract

This paper reports the effects of non-ionic surfactant, Triton-X-100 (Triton), on the etching of Si (100) and (110) in 5, 15, 30, and 48 wt% potassium hydroxide (KOH) solutions. In a pure 5 wt% KOH solution, micropyramids are visible on the Si (100) etched surface. A roof-like shape appears on the Si (110) etched surface. However, in 5 wt% KOH with addition of ppb-level Triton, the etched surface became mirror-like. Furthermore, the etching rate decreased greatly when a ppb-level of Triton added to 5 wt% KOH solution. However, for more highly concentrated KOH solutions, the Triton effect became less effective. From activation energy change obtained from the results, it is apparent that ppb-level Triton in lower concentration KOH solutions adsorbed onto the silicon surface and made the etching from reaction-limited to diffusion-limited process. On the other hand, for higher concentration KOH solutions, Triton seems to lose the function because the activation energy remained in a level of reaction-limited process.