Transistor Element With Laterally Graded Dopant Profile
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The reduction of critical dimensions in semiconductor devices leads to reliability issues, such as degradation and premature failure due to hot carrier injection at increased supply voltages, particularly in input/output portions of complex integrated circuits.
Innovation Solution
A laterally graded dopant profile is implemented at the edge regions of transistor elements, achieved through controlled incorporation of dopant species using masked implantation processes and diffusion techniques, to reduce the lateral electric field and enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If critical dimensions are reduced to increase packing density and performance, then transistor switching speed and packing density are improved, but reliability deteriorates due to hot carrier injection at increased supply voltages
Solution Approach 1:
The patent applies local quality by creating a laterally graded dopant profile specifically at the edge regions of the channel, while maintaining a different dopant concentration in the central channel region. This localized modification of dopant distribution reduces the lateral electric field intensity at the edges where hot carrier injection is most problematic, thereby improving reliability without compromising the overall transistor performance and switching speed achieved through critical dimension reduction
2Adaptability or versatility
If supply voltage is increased to match external signal processing requirements, then compatibility with external signals is improved, but hot carrier injection increases causing degradation and premature failure
Solution Approach 1:
The patent applies parameter changes by modifying the dopant concentration profile as a function of lateral position in the channel. By creating a graded profile where dopant concentration varies laterally (higher at edges, lower in center), the electrical characteristics of the transistor are altered to reduce the lateral electric field intensity. This enables the transistor to operate reliably at higher supply voltages required for external signal compatibility while mitigating hot carrier injection effects through the modified electrical field distribution
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
The graded dopant profile significantly reduces the likelihood of hot carrier injection, thereby improving the long-term reliability of transistor elements even at elevated supply voltages while preserving the basic fully depleted transistor configuration.
Implementation Method 1
achieved through controlled incorporation of dopant species using masked implantation processes and diffusion techniques
Data Source
AI summary
In sophisticated semiconductor devices, the lateral electric field in fully depleted transistor elements operated at elevated supply voltages may be significantly reduced by establishing a laterally graded dopant profile at edge regions of the respective channel regions. In some illustrative embodiments to this end, one or more dopant species may be incorporated prior to completing the gate electrode structure.