Complementary Transistor Gate Stack With Dipole Film Work-Function Tuning
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Solution Overview
Problem
As semiconductor devices continue to shrink in size, the integration of complementary transistors with reduced feature sizes poses challenges in achieving optimal work function and threshold voltage, particularly in forming FinFETs and other types of transistors, where existing methods struggle to efficiently incorporate dipole films for tuning work function without compromising transistor size and performance.
Innovation Solution
The formation of complementary transistors with a common gate electrode, where a thin dipole film is deposited between the interfacial layer and the high-k dielectric layer, allowing for the incorporation of dipole dopants to adjust the work function effectively, without requiring additional annealing processes and maintaining a thin film thickness to accommodate smaller transistor sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dipole films are incorporated to tune work function in complementary transistors, then work function and threshold voltage can be effectively adjusted, but the process complexity increases and additional steps are required
Solution Approach 1:
The patent combines the formation of dipole films with the existing gate dielectric layer deposition process. The dipole film is deposited between the interfacial layer and the high-k dielectric layer, merging multiple functions (work function tuning and gate dielectric formation) into a single integrated process flow, thereby reducing overall process complexity while maintaining precise work function control
Solution Approach 2:
The dipole film is selectively formed only in specific regions where work function adjustment is needed, rather than uniformly across all transistor gates. This localized approach allows precise tuning of threshold voltage in complementary transistors without unnecessarily complicating the entire fabrication process
2Area of moving object
If feature sizes are reduced to increase integration density, then more components can be integrated, but achieving optimal work function and threshold voltage becomes more difficult
Solution Approach 1:
The patent adjusts the thickness and composition parameters of the dipole film to achieve optimal work function values in scaled-down transistor structures. By carefully controlling the dipole film thickness at the nanometer scale and adjusting its chemical composition, the invention maintains precise work function control even as transistor feature sizes are reduced to increase integration density
Solution Approach 2:
The gate dielectric structure employs composite materials combining interfacial layers, dipole films, and high-k dielectric layers. This composite structure allows independent optimization of each layer's properties to achieve both high integration density through scaling and precise work function control through material composition tuning
3Manufacturing precision
If dipole films are made thicker to improve work function tuning, then threshold voltage control improves, but transistor size increases and performance is compromised
Solution Approach 1:
The patent optimizes the dipole film thickness to a specific narrow range that provides sufficient threshold voltage control while minimizing the increase in transistor size. By precisely controlling the dipole film thickness parameter and adjusting its chemical composition, the invention achieves effective work function tuning without significantly increasing the overall transistor dimensions
Solution Approach 2:
The use of high-k dielectric materials in combination with the dipole film allows for thinner overall gate dielectric structures while maintaining effective work function control. The high-k material's superior dielectric properties compensate for the reduced dipole film thickness, enabling threshold voltage control without increasing transistor size
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 effective tuning of work function and threshold voltage in complementary transistors, allowing for efficient integration of dipole films in high-density semiconductor devices, even at smaller sizes, while maintaining the integrity of the gate stack and enabling a common gate electrode for paired transistors.
Implementation Method 1
a thin dipole film is deposited between the interfacial layer and the high-k dielectric layer
Data Source
AI summary
A method includes forming a source/drain region based on a first portion of a semiconductor region, forming an interfacial layer base on a second portion of the semiconductor region, forming a dipole film on the interfacial layer, depositing a high-k dielectric layer on the dipole film, and depositing a work-function layer on the high-k dielectric layer.