Application of deposited by ALD HfO2 and Al2O3 layers in double-gate dielectric stacks for non-volatile semiconductor memory (NVSM) devices

The feasibility of the application of double-gate dielectric stacks with fabricated by atomic layer deposited (ALD) HfO2 and Al2O3 layers in non-volatile semiconductor memory (NVSM) devices was investigated. Significant improvement in retention at elevated temperatures after the application of ALD high-k oxides was demonstrated. Superior memory window (extrapolated at 10 years) of flat-band voltage (Ufb) value of the order of 2.6 V and 4.55 V at 85 °C, for stack with HfO2 and Al2O3, respectively, was obtained. Moreover, the analysis of conduction mechanisms in the investigated stacks under negative voltage revealed F–N tunneling in the range of high values of electric field intensity and lowering of barrier height with increasing temperature.