Ald aluminum oxide as protective coating against oxidation of LPCVD SiC microhotplates

Here we present a method to strongly reduce the oxidation of conductive polycrystalline silicon carbide (poly-SiC) layers. We employed a thin (45 nm) layer of aluminum oxide (Al₂O₃) as protective coating against oxidation. This layer was deposited by atomic layer deposition (ALD) to achieve a high quality and conformal coating. Microheaters made of nitrogen doped poly-SiC (poly-SiC:N) were oxidized at elevated temperatures in both wet and dry atmospheres. Electrical characterizations of the microheaters show that the proposed coating is able to reduce the oxide growth by a factor of 11 for wet oxidation at 1000 °C.