Variable Thickness SOI Film for Integrated Circuit Drive Current
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current CMOS technology faces challenges in enhancing device drive current while minimizing leakage current, as thicker silicon on insulator layers increase leakage currents, and further enhancements in stress proximity raise gate leakage to unacceptable levels.
Innovation Solution
A variable thickness silicon on insulator film is formed with a recess beneath the MOSFET gate and thicker regions within the source/drain areas, improving stress transfer and charge carrier mobility while reducing leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the thickness of the silicon on insulator layer is increased to enhance drive current, then the drive current (Ion) increases, but the leakage current (Ioff) also increases
Solution Approach 1:
The patent applies local quality by creating a variable thickness silicon layer where the thickness varies spatially: thinner in the channel region under the gate and thicker in the source/drain regions. This allows the channel region to have low leakage current while the source/drain regions provide sufficient thickness for high drive current, thus resolving the contradiction between enhancing Ion and minimizing Ioff
2Power
If the strained source/drain elements are positioned closer to the channel region to increase stress and enhance drive current, then the drive current (Ion) increases, but the gate leakage current increases to unacceptable levels
Solution Approach 1:
The patent positions the strained source/drain elements closer to the channel by utilizing the thicker silicon region, while the gate area maintains a thinner silicon profile. This spatial differentiation allows stress enhancement in the source/drain regions without causing excessive gate leakage, as the gate operates over a thinner silicon layer
Solution Approach 2:
The silicon layer is segmented into distinct thickness regions: a first thickness in the channel area and a second (greater) thickness in the source/drain areas. This segmentation enables independent optimization of each region's properties, allowing close positioning of strained elements near the channel while maintaining acceptable gate leakage through the thinner channel region silicon
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 increases device drive current while minimizing leakage currents, enhancing the Ion/Ioff ratio and improving transistor performance.
Implementation Method 1
improving stress transfer and charge carrier mobility
Data Source
AI summary
An integrated circuit that includes: providing a substrate including a support structure, a dielectric layer, and a variable thickness film processed to include the dielectric layer within a recess of the variable thickness film; forming a gate over the variable thickness film; and forming a channel and a source/drain within the variable thickness film.