Ultra Low-k Properties of Atomic Layer Deposited Amorphous Boron Nitride for Futuristic Inter Metal Dielectric

Here, we report 4 nm thick a-BN films deposited by plasma enhanced atomic layer deposition (PE-ALD) with ultralow κ values of 1.43 (close to that of air, κ = 1) at operation frequencies of 1 MHz. The growth per cycle (GPC) is confirmed to be ~0.12 Å/cycle at 350 °C and the thickness of synthesized film linearly increased with the number of ALD cycles. The RMS roughness is only 1.23 nm even at 30 nm thick of a-BN which indicates the formation of smooth surface of our ALD process. Also, XPS shows the stoichiometric a-BN and TEM, XRD, Raman confirms the amorphous nature of BN. Our results demonstrate that ALD a-BN process holds the potential for application in the realization of next-generation 3D integrated devices.