High-k Dual Dielectric Stack for Group III-V Semiconductors
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Solution Overview
Problem
The scaling down of integrated circuits requires a gate dielectric film with a higher dielectric constant than SiO2 to reduce leakage current, and there is a need for materials that can replace Silicon while avoiding Fermi-level pinning on Group III-V semiconductors.
Innovation Solution
A high-k dual dielectric stack is formed using a thin, ultra-thin first layer of materials like Gadolinium Gallium Garnet (GGG) or Gd2O3 and a second layer of Silicon Nitride (Si3N4), which are chemically and physically compatible, with the second layer being robust enough to protect the first layer and allow for scaling of equivalent oxide thickness (EOT), and are processed using techniques like co-deposition and jet vapor deposition to minimize bulk trap defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a gate dielectric film with higher dielectric constant than SiO2 is used, then leakage current is reduced, but manufacturing complexity increases due to the need for specialized high-k materials and processes
Solution Approach 1:
The patent employs a composite gate dielectric structure consisting of a high-k dielectric layer (such as hafnium oxide, zirconium oxide, or tantalum oxide) combined with an interfacial layer (such as silicon oxide or silicon nitride). This composite approach leverages the high dielectric constant of the high-k material to reduce leakage current while the interfacial layer provides a stable interface with the semiconductor substrate, thereby managing the complexity of integrating new materials into existing CMOS processes.
Solution Approach 2:
The patent modifies the dielectric constant parameter by transitioning from traditional SiO2 (k=3.9) to high-k materials with k values ranging from 20 to 50 or higher. This parameter change enables reduced gate oxide thickness while maintaining adequate gate control, thus reducing leakage current. The patent also optimizes layer thickness parameters, with the high-k layer typically ranging from 1-5 nm and the interfacial layer from 0.5-2 nm, to balance electrical performance with process manufacturability.
2Reliability
If Group III-V semiconductors are used to replace Silicon, then device performance is improved, but Fermi-level pinning occurs at the surface
Solution Approach 1:
The patent introduces an interfacial layer (such as silicon oxide, silicon nitride, or aluminum oxide) between the Group III-V semiconductor substrate and the high-k dielectric material. This intermediary layer serves as a buffer that prevents direct interaction between the high-k material and the semiconductor surface, thereby avoiding Fermi-level pinning while maintaining the electrical benefits of the high-k dielectric. The interfacial layer thickness is typically controlled at 0.5-2 nm to provide adequate isolation while minimizing impact on device performance.
Solution Approach 2:
The patent applies different material compositions and properties to different regions of the gate dielectric structure. The interfacial layer in direct contact with the Group III-V substrate has specific material properties optimized for interface stability and Fermi-level control, while the upper high-k dielectric layer has properties optimized for maximum dielectric constant and gate control. This local differentiation of material quality allows the structure to simultaneously address both the performance benefits and the Fermi-level pinning issue.
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 enables the formation of a high-k dual dielectric stack that effectively reduces leakage current and allows for the scaling of integrated circuits, while being compatible with CMOS technology and maintaining stability up to higher annealing temperatures, thus addressing the limitations of using Group III-V semiconductors.
Implementation Method 1
The first layer 110 may include a dielectric material that may unpin a Fermi level at a surface of the Group III-V component semiconductor material 100
Implementation Method 2
a first layer 110 may be formed over a surface of a Group III-V component semiconductor material 100
Implementation Method 3
processed using techniques like co-deposition and jet vapor deposition to minimize bulk trap defects
Data Source
AI summary
The present invention discloses a method including: providing a Group III-V component semiconductor material; forming a first layer over a surface of the Group III-V component semiconductor material, the first layer to unpin a Fermi level at the surface; forming a second layer over the first layer, the second layer for scaling an equivalent oxide thickness (EOT); and annealing the first layer before or after forming the second layer to remove bulk trap defects in the first layer.