FinFET Doping Through Diffusion and Epitaxy Profile Shaping
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Solution Overview
Problem
The complexity of processing and manufacturing Fin Field-Effect Transistors (FinFETs) increases with the scaling down of Integrated Circuit (IC) technology, requiring advanced methods for forming semiconductor fins, doping, and epitaxy to achieve improved performance and efficiency.
Innovation Solution
The method involves forming semiconductor strips, depositing doped dielectric layers, performing annealing to diffuse dopants, and re-growing epitaxy regions to create source/drain regions with optimized profiles, which reduces resistance and enhances FinFET performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional doping and epitaxy methods are used in FinFET manufacturing, then the basic device structure can be formed, but the resistance values remain high and drive currents are insufficient
Solution Approach 1:
The patent segments the doping process into multiple sequential steps with different dopant concentrations. First, a higher concentration dopant is introduced to establish the base doping level, then a lower concentration dopant is introduced to refine the profile. This segmentation allows precise control over the final dopant distribution, resolving the contradiction between achieving reliable device performance and maintaining manufacturing precision.
Solution Approach 2:
The patent applies preliminary action by performing the first doping step before the second doping step. The initial higher concentration doping establishes a foundation that is subsequently refined by the lower concentration doping. This sequential preliminary action enables precise control over the final dopant profile while achieving the desired device performance characteristics.
2Productivity
If dopant concentration is increased to improve drive currents, then FinFET performance improves, but resistance values may increase and manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by introducing different dopant concentrations at different locations and stages of the process. The first doping step uses a higher concentration to establish the base level, while the second doping step uses a lower concentration to refine specific regions. This local differentiation optimizes drive current while managing resistance and processing complexity through targeted doping rather than uniform high-concentration doping throughout.
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 improved FinFET performance by adjusting dopant concentrations and reducing resistance values, leading to better drive currents and overall efficiency in IC manufacturing.
Implementation Method 1
performing an anneal, wherein a dopant in the doped dielectric layer is diffused into the semiconductor region to form a diffused semiconductor region
Implementation Method 2
performing an epitaxy to regrow source/drain regions
Data Source
AI summary
A method includes etching a semiconductor substrate to form a first trench and a second trench. A remaining portion of the semiconductor substrate is left between the first trench and the second trench as a semiconductor region. A doped dielectric layer is formed on sidewalls of the semiconductor region and over a top surface of the semiconductor region. The doped dielectric layer includes a dopant. The first trench and the second trench are filled with a dielectric material. An anneal is then performed, and a p-type dopant or an n-type dopant in the doped dielectric layer is diffused into the semiconductor region to form a diffused semiconductor region.