Charge trapping characteristics of high-relative permittivity (high-κ) HfO 2 films with Al 2 O 3 as a blocking oxide in p-Si/SiO 2 /HfO 2 /Al 2 O 3 /metal memory structures have been investigated. All high-κ films have been grown by atomic layer deposition. A transmission electron microscope image shows that the HfO 2 film is polycrystalline, while the Al 2 O 3 film is partially crystalline after a high temperature annealing treatment at 1000 • C for 10 s in N 2 ambient. A well-behaved counter-clockwise capacitance-voltage hysteresis has been observed for all memory capacitors. A large memory window of ∼7.4 V and a high charge trapping density of ∼1.1 × 10 13 cm −2 have been observed for high-κ HfO 2 charge trapping memory capacitors. The memory window and charge trapping density can be increased with increasing thickness of the HfO 2 film. The charge loss can be decreased using a thick trapping layer or thick tunnelling oxide. A high work function metal gate electrode shows low charge loss and large memory window after 10 years of retention. High-κ HfO 2 memory devices with high-κ Al 2 O 3 as a blocking oxide and a high work function metal gate can be used in future high-density non-volatile memory device applications.

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