Silicon Germanium Fin Diffusion for FinFET Scaling
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Solution Overview
Problem
Conventional planar FETs have reached scaling limits, necessitating the development of unconventional geometries like finFETs for continued performance improvements in semiconductor devices, but existing methods struggle to effectively integrate germanium into fin structures for enhanced performance.
Innovation Solution
A method is disclosed for forming silicon germanium fin structures by creating a germanium layer on silicon fin structures and diffusing germanium into the silicon to convert the fin structures into silicon germanium, which enhances the germanium content and improves device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional planar FET scaling is continued, then device performance improvement is limited, but transitioning to finFET geometry increases manufacturing complexity
Solution Approach 1:
The fin structure is segmented into distinct regions (source, channel, drain) with different germanium concentrations. The source and drain regions are segmented to have higher germanium content than the channel region, allowing optimized performance in each segment while managing the overall device complexity.
Solution Approach 2:
Different regions of the fin structure are assigned different material compositions - the source and drain regions have higher germanium content while the channel has lower germanium content. This local quality variation optimizes carrier transport in source/drain while maintaining channel performance, resolving the contradiction between performance improvement and manufacturing complexity.
2Reliability
If germanium is added to fin structures to enhance performance, then device performance improves, but controlling germanium distribution precision becomes difficult
Solution Approach 1:
A germanium-containing layer is deposited on the fin structure before final processing steps. This preliminary action ensures germanium is present in the source and drain regions before subsequent manufacturing steps, making it easier to achieve the desired germanium distribution without requiring precise control during later high-precision steps.
Solution Approach 2:
The germanium distribution is achieved through self-service mechanisms where the germanium-containing layer naturally distributes germanium to the source and drain regions during thermal processing. The material composition gradients form automatically through diffusion and phase separation, reducing the need for external precision control mechanisms.
3Reliability
If germanium content in fin structures is increased to improve performance, then device performance improves, but manufacturing process complexity increases
Solution Approach 1:
The manufacturing process utilizes parameter changes in the germanium-containing layer composition and thickness to control the final germanium distribution. By adjusting deposition parameters and thermal processing conditions, the desired germanium content in source and drain regions is achieved without requiring fundamentally new manufacturing processes, thus improving performance while maintaining reasonable manufacturing simplicity.
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 allows for the formation of silicon germanium fin structures with increased germanium content, enabling improved performance and scalability of finFETs by optimizing the germanium distribution within the fin structures.
Implementation Method 1
Germanium is then diffused from the germanium including layer into the silicon including fin structure to convert the silicon including fin structure to a silicon germanium including fin structure
Data Source
AI summary
A method of forming a semiconductor device that includes forming a silicon including fin structure and forming a germanium including layer on the silicon including fin structure. Germanium is then diffused from the germanium including layer into the silicon including fin structure to convert the silicon including fin structure to silicon germanium including fin structure.