Improved film growth and flatband voltage control of ALD HfO/sub 2/ and Hf-Al-O with n/sup +/ poly-Si gates using chemical oxides and optimized post-annealing

We demonstrate for the first time that chemical oxide underlayers /spl sim/5 /spl Aring/ thick provide improved growth and flatband voltage control of ALD HfO/sub 2/ films compared to thermal oxides. Optimized annealing conditions are shown to greatly reduce both fixed charge and interfacial oxide growth in the high-/spl kappa/ stacks. Extremely small flatband voltage shifts of <30 mV are achieved, corresponding to a very low fixed charge of Q/sub f//spl sim/2E11/cm/sup 2/.