Transferable silicon nitride microcavities

Abstract

The ability to construct self-supporting or suspended structures is essential for many micro-electro-mechanical systems (MEMS). Well-established technologies exist for the fabrication of such structures using deposition of SiN x grown by low-pressure chemical vapour deposition (LPCVD). However, such techniques are not suitable for temperature-sensitive substrates. While lower process temperatures (<300°C) can be achieved through plasma-enhanced chemical vapour deposition (PECVD), restrictions may still be imposed on the order in which processing steps can occur, making difficult or even prohibiting the use of MEMS technology for semiconductor materials such as HgCdTe (MCT). A novel self-supporting SiN x membrane technology that can be applied to temperature-sensitive semiconductor devices has been developed. To demonstrate this technology, a microcavity structure was constructed on a reusable GaAs substrate. The structure was then removed and bonded via van der Waals forces to a new substrate.