Atomic layer deposited high quality AlN thin films for efficient thermal management

With the development of high-power devices, thermal management has become extremely important for modern electronics. Due to the tiny sizes of components, heat transfer from hot-spots on miniaturized and integrated devices has become an essential issue. Aluminum nitride (AlN), a ceramic material with high thermal conductivity and wide band gap has become a promising choice for thermal management in electronic devices. In this paper, we utilized thermal atomic layer deposition (ALD) to fabricate nanometer scale AlN films on Si and Al plates. Good crystallinity of the ALD AlN films was proved by an X-ray rocking curve with a full width at half-maximum of 0.005 degrees for the (100) crystal plane of AlN. Regular crystal fringes and diffraction stripes could be clearly observed using a high resolution transmission electron microscope. Breakdown voltage and thermal properties of the ALD AlN films were investigated using a Hipot Tester, time-domain thermoreflectance technique and T3ster system. In particular, the measured thermal conductivity of the 2000-cycle ALD AlN film reached 240.77 W m-1 K-1. This thermal conductivity value is better than those of most AlN films fabricated by other methods (with much larger thicknesses). Furthermore, the impressive performances of ALD AlN films in T3ster tests also suggested their promising applications in high power devices for efficient heat removal. With the development of high-power devices, thermal management has become extremely important for modern electronics.