Co-doped Source Drain Structures for Sub-10nm Leakage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional integrated circuit fabrication processes face challenges in scaling to sub-10 nanometer nodes due to variability and limitations in source and drain structure performance, particularly in maintaining low resistivity and short channel control, leading to increased external resistance and leakage current.
Innovation Solution
The use of selective, epitaxial phosphorus and arsenic co-doped silicon source or drain structures, which incorporate both phosphorous and arsenic as dopants to achieve lower defect concentrations and resistivity, minimizing dopant diffusion and enhancing short channel control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional doping processes are used to reduce source and drain resistivity, then material resistivity decreases, but dopant diffusion increases causing short channel control loss and leakage current
Solution Approach 1:
The patent changes the chemical composition parameters by introducing a dual-dopant system (phosphorus and arsenic) instead of single dopant. The phosphorus provides high solubility for low resistivity, while arsenic forms precipitates that act as diffusion barriers, resolving the contradiction between achieving low resistivity and preventing dopant diffusion
Solution Approach 2:
The patent creates a composite doping structure where phosphorus and arsenic work together in a synergistic manner. The arsenic-rich precipitates form a composite phase within the silicon lattice that serves as a diffusion barrier, while the phosphorus provides the necessary carrier concentration for low resistivity
2Reliability
If higher dopant concentrations are used to achieve lower resistivity, then electrical conductivity improves, but defect concentrations increase leading to increased external resistance
Solution Approach 1:
The patent converts the harmful effect of excess dopant atoms (which would normally create defects) into a beneficial diffusion barrier mechanism. The undissolved arsenic atoms form precipitates that, rather than being mere defects, serve as effective diffusion barriers that prevent phosphorus migration while maintaining low resistivity through the dissolved phosphorus component
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 results in significantly reduced material resistivity, improved device performance, and effective short channel control, addressing the limitations of previous methods by maintaining low resistivity without sacrificing dopant activation or increasing external resistance.
Implementation Method 1
The use of selective, epitaxial phosphorus and arsenic co-doped silicon source or drain structures
Implementation Method 2
incorporate both phosphorous and arsenic as dopants to achieve lower defect concentrations and resistivity
Implementation Method 3
minimizing dopant diffusion and enhancing short channel control
Data Source
AI summary
Integrated circuit structures having source or drain structures with phosphorous and arsenic co-dopants are described. In an example, an integrated circuit structure includes a fin having a lower fin portion and an upper fin portion. A gate stack is over the upper fin portion of the fin, the gate stack having a first side opposite a second side. A first source or drain structure includes an epitaxial structure embedded in the fin at the first side of the gate stack. A second source or drain structure includes an epitaxial structure embedded in the fin at the second side of the gate stack. The first and second source or drain structures include silicon, phosphorous and arsenic, with an atomic concentration of phosphorous substantially the same as an atomic concentration of arsenic.