Fabrication and characterisation of CMOS-compatible tungsten nanobolometers

We demonstrate the use of tungsten metal as a CMOS-compatible nanobolometer and microbolometer resistor material. Our tungsten bolometer devices use serpentine resistor designs, with 125 nm film thicknesses and feature critical dimensions (CDs) ranging from 80 nm to 350 nm. Our sensor meanders were patterned using electron beam lithography (EBL) and integrated within a 0.5 μm triple level metal (TLM) CMOS fabrication process. We thermally isolated our sensor structures from the wafer substrate using MEMS-based silicon bulk micromachining (SBM). We present temperature coefficient of resistance (TCR) and physical data showing stable SiO₂-encapsulated tungsten nanobolometer performance under current stress conditions. Our tungsten devices demonstrate the potential of tungsten as a CMOS-compatible nanobolometer and microbolometer material.