Piezoresistive PtSe${}_2$ pressure sensors with reliable high sensitivity and their integration into CMOS ASIC substrates

Abstract

Membrane-based sensors are an important market for microelectromechanical systems (MEMS). Two-dimensional (2D) materials, with their low mass, are excellent candidates for suspended membranes to provide high sensitivity, small footprint sensors. The present work demonstrates pressure sensors employing large-scale-synthesized 2D platinum diselenide (PtSe${}_2$) films as piezoresistive membranes supported only by a thin polymer layer. We investigate three different synthesis methods with contrasting growth parameters and establish a reliable high yield fabrication process for suspended PtSe${}_2$/PMMA membranes across sealed cavities. The pressure sensors reproducibly display sensitivities above 6 x 10${}^4$ kPa${}^{-1}$. We show that the sensitivity clearly depends on the membrane diameter and the piezoresistive gauge factor of the PtSe${}_2$ film. Reducing the total device size by decreasing the number of membranes within a device leads to a significant increase in the area-normalized sensitivity. This allows the manufacturing of pressure sensors with high sensitivity but a much smaller device footprint than the current state-of-the-art MEMS technology. We further integrate PtSe${}_2$ pressure sensors with CMOS technology, improving the technological readiness of PtSe${}_2$-based MEMS and NEMS devices.

42 pages