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

TL;DR

This paper presents the development of high-sensitivity, miniaturized pressure sensors using large-scale-synthesized PtSe₂ 2D films, with reliable fabrication methods and integration into CMOS ASIC substrates, advancing MEMS technology.

Contribution

It introduces a reliable fabrication process for PtSe₂-based pressure sensors with high sensitivity and demonstrates their integration into CMOS ASICs, enhancing MEMS device capabilities.

Findings

Pressure sensors with sensitivities above 6 x 10^4 kPa^-1 were achieved.

Sensor sensitivity depends on membrane diameter and piezoresistive gauge factor.

Smaller device size increases area-normalized sensitivity.

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.