SiGe Surface Layer for High-k Dielectric Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The integration of high-k dielectric materials into semiconductor devices often results in uncontrolled growth of a SiO2 interfacial layer, which increases the overall dielectric constant and reduces the effectiveness of the high-k material, as well as causing substrate oxidation, making it challenging to maintain the desired gate oxide thickness and transistor performance.
Innovation Solution
A SiGe surface layer is formed on the substrate to prevent oxidation, allowing for direct deposition of a high-k dielectric layer without a base oxide layer, and an oxide layer is formed between the high-k dielectric and the SiGe surface layer during deposition or annealing, controlling the interfacial layer thickness and maintaining low equivalent gate oxide thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a high-k dielectric layer is deposited directly onto a Si substrate, then the physical thickness of the gate dielectric can be increased, but an uncontrolled thick oxide interfacial layer forms that increases the equivalent gate oxide thickness and reduces device performance
Solution Approach 1:
The gate dielectric structure is segmented into multiple functional layers: a thin controlled oxide interfacial layer (5-15 Å) formed by oxidation of SiGe, and a thicker high-k dielectric layer deposited thereon. This segmentation allows the total physical thickness to be increased while keeping the effective gate oxide thickness low through the high-k material's superior dielectric properties.
Solution Approach 2:
A SiGe surface layer is introduced as an intermediary between the Si substrate and the high-k dielectric layer. This SiGe layer serves as a buffer that enables controlled formation of a thin oxide interfacial layer during subsequent oxidation, preventing uncontrolled thick oxide growth while allowing the high-k dielectric to be deposited with precise thickness control.
2Adaptability or versatility
If a high-k dielectric layer is integrated into the semiconductor device, then the dielectric constant increases which should improve device performance, but the formation of an oxide interfacial layer lowers the overall dielectric constant
Solution Approach 1:
The oxidation of the SiGe surface layer, which initially appears harmful as it forms an oxide interfacial layer, is converted into a beneficial process. The SiGe oxidation produces a thin, controlled oxide layer (5-15 Å) with excellent interface properties, while the SiGe layer itself protects the underlying Si substrate from excessive oxidation. This controlled oxidation is essential for forming a high-quality interface for the high-k dielectric.
Solution Approach 2:
The gate dielectric structure employs a composite material architecture consisting of multiple layers with different properties: the oxide interfacial layer provides excellent interface quality, the SiGe buffer layer prevents substrate oxidation, and the high-k dielectric layer provides superior dielectric constant. This composite structure achieves both low equivalent oxide thickness and high dielectric constant.
3Manufacturing precision
If the oxide interfacial layer is made thin to maintain low equivalent gate oxide thickness, then device performance improves, but the oxidation process becomes difficult to control
Solution Approach 1:
The oxidation process parameters are optimized by using SiGe as the substrate material instead of pure Si. The presence of Ge in SiGe modifies the oxidation kinetics, enabling controlled formation of thin oxide layers (5-15 Å) at lower temperatures and with better thickness uniformity. This parameter change in substrate composition makes the oxidation process more controllable for achieving the desired thin interfacial layer.
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 substrate oxidation and maintains a low overall dielectric constant, enhancing the reliability and performance of semiconductor devices by allowing for increased physical thickness of the gate dielectric layer while maintaining equivalent gate oxide thickness below 10 angstroms.
Implementation Method 1
A SiGe surface layer is formed on the substrate to prevent oxidation
Implementation Method 2
an oxide layer is formed between the high-k dielectric and the SiGe surface layer during deposition or annealing
Implementation Method 3
direct deposition of a high-k dielectric layer
Data Source
AI summary
A method for using a silicon germanium (SiGe) surface layer to integrate a high-k dielectric layer into a semiconductor device. The method forms a SiGe surface layer on a substrate and deposits a high-k dielectric layer on the SiGe surface layer. An oxide layer, located between the high-k dielectric layer and an unreacted portion of the SiGe surface layer, is formed during one or both of deposition of the high-k dielectric layer and an annealing process after deposition of the high-k dielectric layer. The method further includes forming an electrode layer on the high-k dielectric layer.