Seeded Hafnium Oxide Capacitor Stack for Low-Leakage Memory Cells

The patent employs a composite dielectric structure consisting of multiple layers including hafnium oxide layers, zirconium oxide layers, and seed layers. This composite approach combines the high dielectric constant of hafnium oxide with the beneficial properties of zirconium oxide and seed layers to achieve both high capacitance and low leakage current, overcoming the limitations of single-material solutions

The patent introduces different material compositions and structures at different locations within the dielectric layer stack. Specifically, seed layers with specific crystal structures are placed at interfaces to control local properties, while bulk layers provide overall dielectric function. This local differentiation allows optimization of both capacitance and leakage characteristics in different regions of the same structure

The patent introduces seed layers containing pre-formed crystal structures (such as tetragonal zirconium oxide or cubic hafnium oxide) before the main dielectric layer deposition. These seed layers act as templates that guide the crystallization of subsequent layers, enabling low-temperature crystallization without requiring high-temperature annealing processes. This preliminary structuring simplifies the manufacturing process while ensuring desired crystal structure stability

The patent changes the crystallization temperature parameter from conventional high temperatures to low temperatures by introducing seed layers. This parameter change is achieved through the nucleation effect of seed layers, which provide ready-made crystal structures that reduce the energy barrier for crystallization, allowing the process to proceed at lower temperatures with reduced manufacturing complexity