High-k Dielectric Interface Layer Formation and Annealing
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Solution Overview
Problem
Conventional methods for forming high dielectric constant materials in semiconductor devices face challenges such as interfacial oxide degradation, increased effective oxide thickness, and decreased dielectric constant, particularly due to the use of silicon dioxide and materials like LaAlO3 and LaScO3, which exhibit poor thermal stability and non-stoichiometric issues.
Innovation Solution
A method involving the formation of a well-controlled interface layer through thermal oxidation, followed by wet etching and high-temperature annealing to densify the oxide, and optionally nitridation, to create a high k dielectric material stack with a nitrided interface layer that maintains thermal stability and reduces effective oxide thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If silicon dioxide is used as dielectric material, then manufacturing simplicity is maintained, but dielectric constant is limited to 3.9
Solution Approach 1:
The patent uses composite material structures including high-k dielectric materials (hafnium oxide, hafnium silicate) combined with silicon dioxide in specific layer configurations. This allows achieving higher effective dielectric constants while maintaining compatibility with existing silicon-based semiconductor manufacturing processes
Solution Approach 2:
The patent changes the dielectric constant parameter by introducing high-k materials with k values of 25-40 (hafnium oxide, hafnium silicate) to replace or supplement silicon dioxide (k=3.9), thereby increasing the overall dielectric constant of the gate dielectric stack
2Reliability
If high k dielectric materials like hafnium oxide are used, then dielectric constant increases to around 30, but thermal stability deteriorates
Solution Approach 1:
The patent employs composite dielectric stacks combining high-k materials (hafnium oxide, hafnium silicate) with thermally stable silicon dioxide layers. The silicon dioxide provides thermal stability while the high-k materials provide high dielectric constant, achieving both requirements simultaneously
Solution Approach 2:
The patent introduces silicon dioxide as an intermediary layer between the high-k dielectric material and the silicon substrate. This intermediary layer protects the high-k material from thermal degradation during subsequent processing while maintaining the high dielectric constant benefit
3Stability of the object's composition
If interface layer is formed by thermal oxidation, then stoichiometric integrity is improved, but effective oxide thickness increases
Solution Approach 1:
The patent changes the interface layer formation parameters by using wet chemical etching instead of thermal oxidation, and by controlling annealing temperature and atmosphere. This produces a thinner interface layer with appropriate stoichiometry, reducing effective oxide thickness while maintaining compositional integrity
Solution Approach 2:
The patent performs preliminary wet etching of the interface layer before final dielectric material deposition. This preliminary action removes excess oxide and creates a controlled thin interface layer, preventing excessive effective oxide thickness buildup
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 approach results in a high k dielectric material with low leakage current and excellent thermal stability, minimizing effective oxide thickness growth and ensuring stoichiometric integrity, thereby enhancing the performance of semiconductor devices like capacitors and transistors.
Implementation Method 1
annealing the interface layer
Implementation Method 2
forming an interface layer
Implementation Method 3
optionally nitridation, to create a high k dielectric material stack with a nitrided interface layer
Data Source
AI summary
Semiconductor devices and methods of manufacture thereof are disclosed. A preferred embodiment comprises a method of forming an insulating material layer. The method includes forming an interface layer, removing a portion of the interface layer, annealing the interface layer, and forming a dielectric material over the interface layer.