Atomic Layer Deposited Ultrathin HfO[sub 2] and Al[sub 2]O[sub 3] Films as Diffusion Barriers in Copper Interconnects

Atomic layer deposited ultrathin and films were studied as diffusion barriers between Cu and Si substrate. The thermal stability of 3 nm thick and films was investigated after annealing at different temperatures for in . X-ray diffraction analyses and sheet resistance measurements suggest that both barrier films were thermally stable and the formation of started to take place only after annealing at high temperatures. Specifically, our results show that 3 nm thick and diffusion barriers break down after annealing in at 700 and , respectively.