Fin-FET Graded Doping Profile for Leakage Reduction
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Solution Overview
Problem
Conventional tri-gate transistors face challenges in controlling the doping concentration gradient as the distance between junctions reduces to 10 nm or less, making it difficult to maintain precise control over the doping concentration in the channel region.
Innovation Solution
A fin-type field effect transistor with a graded doping profile is developed, where the doping concentration in the channel region decreases with increasing distance from the top surface and sidewalls, following an error function or Gaussian distribution, and the source and drain regions have a uniform doping concentration greater than or equal to the maximum in the channel region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the distance between junctions is reduced to 10 nm or less, then the device size is reduced, but the control of doping concentration gradient becomes increasingly difficult
Solution Approach 1:
The patent applies local quality by creating a non-uniform doping concentration distribution within the channel region. Specifically, the doping concentration is designed to be higher near the top surface and sidewalls and lower in the bulk region, forming a spatially varying doping profile that is optimized for each local region's electrical characteristics. This resolves the contradiction by enabling precise control of electrical properties in the miniaturized device structure.
Solution Approach 2:
The patent changes the doping concentration parameter from a uniform distribution to a graded distribution that varies spatially within the channel region. By implementing a doping profile where concentration decreases from the surface toward the bulk, the patent achieves better control over the doping gradient in sub-10nm devices, resolving the manufacturing precision issue while maintaining device miniaturization.
2Reliability
If conventional tri-gate transistor structure is used, then the device can operate, but the on-off drain current ratio is insufficient and leakage current is high
Solution Approach 1:
The patent applies local quality by creating a non-uniform doping concentration distribution within the channel region. Specifically, the doping concentration is designed to be higher near the top surface and sidewalls and lower in the bulk region, forming a spatially varying doping profile that is optimized for each local region's electrical characteristics. This resolves the contradiction by enabling precise control of electrical properties in the miniaturized device structure.
Solution Approach 2:
The patent changes the doping concentration parameter from a uniform distribution to a graded distribution that varies spatially within the channel region. By implementing a doping profile where concentration decreases from the surface toward the bulk, the patent achieves better control over the doping gradient in sub-10nm devices, resolving the manufacturing precision issue while maintaining device miniaturization.
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 improves the on-off drain current ratio and reduces leakage current, enhancing the switching characteristics of the transistor while allowing for reduced production costs by using a bulk silicon substrate.
Implementation Method 1
The doping concentration gradient is governed by the laws of diffusion law and the statistical distribution of dopant atoms
Implementation Method 2
performing a high-temperature annealing so as to allow the impurity in the doped layer to diffuse into the semiconductor body
Data Source
AI summary
A fin-type field effect transistor includes a semiconductor body formed on a substrate, the semiconductor body having a top surface and a pair of laterally opposite sidewalls, and a gate electrode formed above the sidewalls and the top surface of the semiconductor body. The semiconductor body further includes a source region formed on an end portion of the semiconductor body, a drain region formed on another end portion of the semiconductor body, and a channel region formed between the source region and the drain region and surrounded by the gate electrode, wherein a doping concentration of the channel region decreases with increasing distance from the top surface and the sidewalls.