access icon free Effective improvement in the etching characteristics of Si{110} in low concentration TMAH solution

An aqueous tetramethylammonium hydroxide (TMAH) solution is widely used for silicon wet anisotropic etching to perform bulk micromachining for the fabrication of microstructures on a silicon wafer. To reduce the etching time to increase the productivity, etchant must provide high etch rate. In the present work, the etching characteristics of Si{110} in low concentration TMAH (5 wt%) with the addition of various concentrations (5–20%) of reducing agent hydroxylamine (NH2OH) have been studied to increase the etch rate of Si{110} to reduce the etch time for the fabrication of microstructures. Moreover, it is aimed to enhance the undercutting at convex corner for the fast release of the structure. The etch rate of Si{110} and the undercutting at convex corners with the addition of NH2OH increases by more than three times that in pure TMAH. In addition to the etch rate and undercutting, the effect of NH2OH on etched surface morphology is investigated systematically. The present study is focused to enhance the application of wet etching in silicon micromachining for the fabrication of various kinds of microstructures for applications in microelectromechanical systems.

Inspec keywords: surface morphology; micromachining; crystal microstructure; nanofabrication; sputter etching; silicon; elemental semiconductors; micromechanical devices

Other keywords: etched surface morphology; microstructures; silicon wafer; microelectromechanical systems; bulk micromachining; silicon micromachining; Si; low concentration TMAH solution; etching characteristics; silicon wet anisotropic etching; reducing agent hydroxylamine; aqueous tetramethylammonium hydroxide solution

Subjects: Surface treatment and degradation in semiconductor technology; Solid surface structure; Methods of nanofabrication and processing; Microstructure; Elemental semiconductors; Low-dimensional structures: growth, structure and nonelectronic properties; Micromechanical and nanomechanical devices and systems; Fabrication of MEMS and NEMS devices; Surface treatment (semiconductor technology)

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