A modular system of SiC-based microhotplates for the application in metal oxide gas sensors

A modular system of SiC-based microhotplates with integrated IDC for the use in metal oxide gas sensors is presented. Basic building block of the sensors is a 1 μm thick polycrystalline 3C-SiC membrane, which acts as supporting structure. A 200 nm thick HfB2 thin film heater with a dc-resistance of about 12 Ω (1–2 V operating voltage) or alternatively an N-doped area in the SiC-membrane (12 V operating voltage) is used as hotplate. The active part of the membrane is separated from the surrounding membrane by six SiC-microbridges of 150 μm length and widths of 10, 20 and 40 μm. The heater is designed for operating temperatures up to 700°C and can be operated at about 400°C with a power of 35 mW.