Piezoresistive Platinum Diselenide Pressure Sensors with Reliable High Sensitivity and Their Integration into Complementary Metal-Oxide-Semiconductor Circuits

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 (PtSe₂) 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 PtSe₂/PMMA membranes across sealed cavities. The pressure sensors reproducibly display sensitivities above 6 × 10^–4 kPa^–1. We show that the sensitivity clearly depends on the membrane diameter and the piezoresistive gauge factor of the PtSe₂ 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 PtSe₂ pressure sensors with CMOS technology, improving the technological readiness of PtSe₂-based MEMS and NEMS devices.