Achieving low sheet resistance in Si-doped AlN via low-temperature MOCVD

A low-temperature (LT) metal-organic chemical vapor deposition (MOCVD) technique was developed for obtaining conductive Si-doped AlN thin films. An optimization of the deposition parameters, such as V/III ratio and trimethylaluminum flow rate, enabled state-of-the-art sheet resistance (RSH) of 0.47 and 0.76 MΩ/□ and contact resistance (RC) of 1.2 × 10−2 and 3 × 10−2 Ω cm2 in 1200 nm n-AlN deposited on bulk AlN and AlN on Sapphire substrate, respectively, with surface roughness below 0.3 nm. The reduced sheet resistance of LT-MOCVD n-AlN indicates lower compensation than high-temperature MOCVD films, establishing LT-MOCVD as an effective route for highly conductive n-AlN thin films.