Semiconductor device and method for fabricating the same
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Solution Overview
Problem
Current semiconductor memory devices face limitations in reducing memory cell area and operating voltage, with zirconium oxide's inability to increase capacitance effectively, necessitating the development of high-k materials with high dielectric constants and low leakage currents.
Innovation Solution
A dielectric layer stack comprising hafnium oxide layers, seed layers, and a thermal source layer, where the hafnium oxide layers are crystallized at low temperatures using a seed layer and thermal source layer, eliminating the need for high-temperature annealing and enhancing capacitance while suppressing leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If zirconium oxide is used as a dielectric layer, then the device structure is simple and easy to manufacture, but the capacitance cannot be increased effectively
Solution Approach 1:
The patent employs a composite dielectric layer structure consisting of multiple hafnium oxide layers with different crystal phases (tetragonal and monoclinic) and varying doping levels. This composite structure achieves high capacitance through the high dielectric constant of hafnium oxide while maintaining manufacturability through standardized deposition and annealing processes.
2Quantity of substance
If high-temperature annealing is used to crystallize hafnium oxide, then the dielectric constant is improved, but the manufacturing process becomes complex and costly
Solution Approach 1:
The patent utilizes parameter changes by controlling the annealing temperature within a specific range (400°C to 600°C) and adjusting the duration and atmosphere to achieve the desired crystal phase transformation. This optimized parameter set achieves high dielectric constant without requiring excessive temperature, thereby simplifying the manufacturing process.
Solution Approach 2:
The patent applies preliminary action by forming a seed layer or using a thermal source layer before the main annealing process to initiate and control the crystallization of hafnium oxide. This preliminary preparation enables the dielectric layer to achieve the desired crystal structure at lower temperatures, reducing process complexity.
3Area of moving object
If the memory cell area is reduced to increase integration, then the device density improves, but the capacitance and performance deteriorate
Solution Approach 1:
The patent changes the material parameter from conventional dielectrics to high-k hafnium oxide, which provides superior dielectric properties. This material substitution enables achieving high capacitance in a reduced area, thus improving integration density without sacrificing performance.
4Use of energy by moving object
If the operating voltage is reduced, then the power consumption decreases, but the leakage current becomes more significant
Solution Approach 1:
The patent uses a composite structure with multiple hafnium oxide layers having different crystal phases and doping levels. This composite architecture provides both high dielectric constant for low power operation and sufficient barrier properties to suppress leakage current, achieving a balance between power consumption and leakage control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves a high dielectric constant and low leakage current, enabling increased capacitance and improved effective work function without the drawbacks of high-temperature processing, thus addressing the limitations of existing technologies.
Implementation Method 1
the hafnium oxide layers are crystallized at low temperatures using a seed layer and thermal source layer
Implementation Method 2
a dielectric layer stack having a high dielectric constant and a low leakage current
Data Source
AI summary
A capacitor of a semiconductor device may include a first electrode, a second electrode, and a dielectric layer stack positioned between the first electrode and the second electrode and including at least one embedded doping level and at least one interface doping level, wherein the dielectric layer stack may include a plurality of hafnium oxide layers, a plurality of seed layers, and a plurality of direct contact interfaces that are in direct contact with the hafnium oxide layers and the seed layers, at least one the embedded doping level is positioned in at least one the hafnium oxide layers, and at least one the interface doping level is positioned at least one the direct contact interfaces.