Scavenging Layer Oxygen Extraction for High-k Dielectric CET Reduction
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Solution Overview
Problem
Current III-V MOS devices have a high capacitance equivalent thickness (CET) of 25 A or higher, which is not suitable for advanced semiconductor devices beyond the 15 nm node, requiring a reduction in oxygen content in high dielectric constant materials to achieve improved capacitive performance.
Innovation Solution
A method involving the formation of a scavenging layer with high oxygen affinity, such as aluminum, on a high dielectric constant material, followed by annealing to form an oxide layer that reduces oxygen content, thereby reducing the CET by at least 5 Angstroms, and subsequent removal of the scavenging layer to enhance capacitive equivalent thickness and equivalent oxide thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high dielectric constant material is used to increase capacitance, then capacitance equivalent thickness increases, but oxygen content in the material increases which degrades capacitive performance
Solution Approach 1:
The patent applies the extraction principle by introducing a scavenging layer that selectively removes oxygen from the high dielectric constant material. The scavenging layer is formed on the high-k dielectric layer, and through annealing, oxygen is extracted from the high-k material and transferred to the scavenging layer, thereby reducing oxygen content in the capacitor dielectric and improving capacitive performance.
Solution Approach 2:
The scavenging layer acts as an intermediary between the high dielectric constant material and the external environment. This intermediate layer facilitates the removal of oxygen from the high-k material without directly exposing it to harmful external factors, enabling controlled oxygen extraction that improves capacitive equivalent thickness while maintaining material integrity.
2Manufacturing precision
If oxygen content is reduced in high dielectric constant material, then capacitive equivalent thickness improves, but additional fabrication steps are required
Solution Approach 1:
The patent applies preliminary action by forming the scavenging layer before final capacitor assembly. The scavenging layer is deposited on the high-k dielectric layer, and annealing is performed to pre-remove oxygen from the high-k material before the capacitor is fully assembled and operational, ensuring optimal capacitive performance from the start.
Solution Approach 2:
The patent utilizes parameter changes by modifying the oxygen concentration in the high dielectric constant material through controlled annealing processes. The annealing temperature, time, and atmosphere are optimized to achieve the desired oxygen removal while maintaining the high-k properties of the dielectric material, thereby improving capacitive equivalent thickness.
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 effectively reduces CET and EOT, enabling the use of III-V and II-VI materials in surface channel devices and improving capacitive performance, specifically achieving a CET of at least 5 Angstroms reduction, suitable for devices beyond the 15 nm node.
Implementation Method 1
forming a scavenging layer on the high dielectric constant material; and annealing to form an oxide layer between the high dielectric constant layer and the scavenging layer such that oxygen in the high dielectric constant material is drawn out to reduce oxygen content
Data Source
AI summary
A device and method for fabricating a capacitive component includes forming a high dielectric constant material over a semiconductor substrate and forming a scavenging layer on the high dielectric constant material. An anneal process forms oxide layer between the high dielectric constant layer and the scavenging layer such that oxygen in the high dielectric constant material is drawn out to reduce oxygen content.