High-k Insulating Layer Thermal Stability in Semiconductor Memory
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Solution Overview
Problem
Conventional semiconductor memory devices experience adverse effects such as leakage current and deteriorated retention characteristics due to the crystallization of high-k materials caused by high temperature annealing processes, which affects the device's operational integrity.
Innovation Solution
Incorporating high-k materials like Hafnium (Hf) silicate, Zirconium (Zr) silicate, Yttrium (Y) silicate, or lanthanum-family metal silicates with specific atomic ratios to maintain thermal stability and prevent crystallization during high temperature annealing, ensuring the high-k insulating layer remains in an amorphous state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperature annealing process is used to activate dopant areas, then dopant activation is improved, but high-k material crystallizes causing leakage current
Solution Approach 1:
The patent changes the chemical composition parameters of the high-k material by forming a composite structure where HfO2 is combined with SiO2 in specific ratios. This compositional modification lowers the crystallization temperature of the high-k layer, allowing it to remain amorphous during standard annealing processes while still achieving adequate dopant activation.
Solution Approach 2:
The patent creates a composite high-k material system by depositing HfO2 layers in contact with SiO2 layers. This composite structure leverages the thermal stability of SiO2 to suppress crystallization of the HfO2 component, enabling the high-k material to maintain its amorphous state during annealing while providing the desired electrical characteristics.
2Duration of action of stationary object
If high-k material is used to improve retention characteristics, then information storage is improved, but crystallization occurs during annealing deteriorating device characteristics
Solution Approach 1:
The patent modifies the thermal stability parameters of the high-k material through compositional engineering. By controlling the HfO2 to SiO2 ratio and adjusting deposition conditions, the material's resistance to crystallization is enhanced, allowing it to maintain amorphous structure at annealing temperatures while preserving high dielectric constant for improved retention.
Solution Approach 2:
The patent employs a composite high-k insulating layer combining HfO2 and SiO2 materials. This composite approach allows the system to achieve both high retention characteristics from the HfO2 component and thermal stability from the SiO2 component, preventing crystallization-induced degradation during device fabrication.
3Object-generated harmful factors
If amorphous high-k material is used to prevent leakage, then insulation is improved, but dopant activation requires high temperature causing crystallization
Solution Approach 1:
The patent changes the thermal response parameters of the high-k material through compositional modification. By incorporating SiO2 with HfO2 in controlled ratios, the material exhibits suppressed crystallization kinetics, allowing dopant activation to occur at reduced temperatures while maintaining the amorphous state necessary for low leakage current.
Solution Approach 2:
The patent utilizes a composite HfO2-SiO2 high-k insulating layer where the SiO2 component acts as a crystallization inhibitor. This composite structure enables the system to achieve adequate dopant activation at lower temperatures without compromising the amorphous nature of the high-k material, thereby preventing leakage current generation.
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
This approach enhances the thermal stability and reduces leakage currents, thereby improving the retention characteristics and electric performance of semiconductor memory devices by maintaining the amorphous state of high-k materials even at high annealing temperatures.
Implementation Method 1
Incorporating high-k materials like Hafnium (Hf) silicate, Zirconium (Zr) silicate, Yttrium (Y) silicate, or lanthanum-family metal silicates with specific atomic ratios to maintain thermal stability and prevent crystallization during high temperature annealing
Implementation Method 2
the upper surfaces of the semiconductor substrate 11 to both sides of the gate are doped with a dopant, for example, boron (B) or phosphorous (P), using an ion implantation method
Implementation Method 3
an annealing process is performed to activate the first and second dopant areas 12a and 12b. For this purpose, the first and second dopant areas 12a and 12b are heated at a high temperature between about 900° C. and 1000° C.
Data Source
AI summary
A semiconductor memory device a first dopant area and a second dopant area, the first dopant area and the second dopant area disposed in a semiconductor substrate, an insulating layer disposed in contact with the first dopant area and the second dopant area, the insulating layer including a material selected from the group consisting of Hf, Zr, Y, and Ln, and a gate electrode layer disposed on the insulating layer.