Adsorbed surfactant thickness on: A Si wafer dominating etching properties of TMAH solution

Abstract

The goal of this article is to study the etching properties as a function of various adsorbed surfactant thickness in wet anisotropic etching process of TMAH solution. The thickness of preferentially adsorbed surfactant molecules on Si{110} and Si{100} has been evaluated by using spectroscopic ellipsometry (SE). The dependence of the etch rate in TMAH and the surface roughness on the layer thickness demonstrates that the surfactant is adsorbed at the interface during etching in TMAH+Triton. A thin pre-adsorbed layer is sufficient to dramatically improve the etching characteristics of silicon.