Ternary Paraelectric Cc Structure for DRAM Leakage Reduction

The patent employs composite dielectric structures combining multiple materials (e.g., HfO2, Al2O3, TiO2) to achieve both high capacitance and low leakage current. The composite structure allows optimization of each layer's properties: HfO2 provides high dielectric constant while Al2O3 and TiO2 layers reduce leakage, thus resolving the contradiction between thinning for integration and preventing leakage.

The patent systematically varies material composition ratios, layer thicknesses, and deposition parameters to optimize the balance between capacitance and leakage. By adjusting the dielectric constant and thickness parameters of different materials in the composite structure, the invention achieves high integration density while maintaining acceptable leakage levels.

The patent uses composite dielectric structures where high-k materials (HfO2, Al2O3) are combined with low-leakage materials (TiO2, SiO2). This composite approach allows the system to benefit from the high dielectric constant of HfO2/Al2O3 for capacitance while the TiO2/SiO2 layers provide leakage suppression, thus resolving the contradiction between maintaining capacitance and reducing leakage.

Different regions of the dielectric stack are assigned different material compositions optimized for their specific functions: the HfO2/Al2O3 layers are optimized for high dielectric constant to provide capacitance, while the TiO2/SiO2 interface regions are optimized for low leakage current. This local optimization of material properties resolves the contradiction between capacitance and leakage.