GAA Channel Stack with Diffusion Blocking for Anti-Punch-Through
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Solution Overview
Problem
The scaling of gate-all-around (GAA) devices in the integrated circuit industry faces challenges such as anti-punch-through implantation issues, dopant diffusion leading to mobility degradation, and performance degradation in high mobility channels, which complicates the manufacturing process and affects device performance.
Innovation Solution
A method for fabricating multigate devices, including the formation of n-type and p-type GAA transistors, involves creating doped wells, a diffusion blocking layer, and shallow trench isolation with a solid doping source material layer to prevent dopant diffusion and enhance anti-punch-through features, along with a metal gate structure that wraps around the semiconductor layers to maintain control and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anti-punch-through implantation is performed in conventional GAA devices, then punch-through effects are reduced, but dopant diffusion occurs in the channel region causing mobility degradation
Solution Approach 1:
A diffusion blocking layer is introduced as an intermediary between the anti-punch-through implantation region and the channel. This layer selectively blocks dopant diffusion into the channel region while allowing the anti-punch-through implantation to occur, thus preventing mobility degradation while maintaining punch-through protection
Solution Approach 2:
The diffusion blocking layer is positioned specifically at the interface between the anti-punch-through region and the channel, providing localized dopant blocking only where needed. This localized approach protects the channel from dopant diffusion while allowing other regions to maintain their doping profiles for proper device operation
2Productivity
If GAA devices are scaled down to improve production efficiency and lower costs, then manufacturing cost decreases, but anti-punch-through implantation cannot be properly implemented and dopant diffusion increases
Solution Approach 1:
The solution transitions from a planar doping approach to a vertical stacking architecture with multiple layers. The diffusion blocking layer is inserted vertically between the anti-punch-through region and the channel, creating a new dimensional solution that addresses scaling challenges in vertically stacked GAA devices
Solution Approach 2:
The device structure becomes a composite with multiple material layers including the diffusion blocking layer made of specific semiconductor materials with different doping characteristics. This composite structure enables simultaneous achievement of proper anti-punch-through implantation and dopant diffusion control in scaled devices
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 addresses the challenges of anti-punch-through implantation and dopant diffusion, improving mobility and device performance while maintaining compatibility with conventional manufacturing processes, thereby enhancing the scalability and efficiency of GAA devices.
Implementation Method 1
a diffusion blocking layer over the substrate and underlying the semiconductor layer stack
Implementation Method 2
The fin active region is then driven into the solid doping source material layer to form an anti-punch-through (APT) feature therein
Data Source
AI summary
Multi-gate devices and methods for fabricating such are disclosed herein. An exemplary method includes forming a diffusion blocking layer on a semiconductor substrate; forming channel material layers over the diffusion blocking layer; patterning the semiconductor substrate, the channel material layers, and the diffusion blocking layer to form a trench in the semiconductor substrate, thereby defining an active region being adjacent the trench; filling the trench with a dielectric material layer and a solid doping source material layer containing a dopant; and driving the dopant from the solid doping source material layer to the active region, thereby forming an anti-punch-through (APT) feature in the active region.