Multi-Threshold Gate Thickness Control for Faster CMOS Switching
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Solution Overview
Problem
Traditional methods of modulating transistor threshold voltage through doping adversely affect switching speed and increase performance variation due to dopant scattering and random fluctuations, limiting the optimization of power dissipation and clock frequency in integrated circuits.
Innovation Solution
The use of varying thicknesses of gate electrode material to modulate threshold voltages instead of doping, allowing for the creation of multi-threshold voltage devices with improved switching speed and reduced performance variation by altering the workfunction without affecting carrier mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If doping is used to modulate threshold voltage, then threshold voltage control is achieved, but switching speed deteriorates due to dopant scattering
Solution Approach 1:
The patent changes the physical parameter of the gate electrode by varying its thickness to modulate the threshold voltage. Thinner gate electrodes result in lower threshold voltages while thicker electrodes yield higher threshold voltages, eliminating the need for doping and its associated negative effects on carrier mobility and switching speed.
2Reliability
If doping levels are increased to achieve desired threshold voltage, then threshold voltage modulation is improved, but performance variation increases due to random dopant fluctuations
Solution Approach 1:
The patent replaces doping-based threshold voltage control with gate electrode thickness control. This parameter change eliminates random dopant fluctuations and their causes, thereby reducing performance variation while maintaining the ability to modulate threshold voltage across different circuit regions.
3Ease of manufacture
If uniform gate electrode thickness is used, then manufacturing is simplified, but multi-threshold voltage devices cannot be created
Solution Approach 1:
The patent applies local quality by varying the gate electrode thickness in different spatial regions to create transistors with different threshold voltages. This is achieved through selective removal or deposition processes that create non-uniform gate structures, enabling multi-threshold voltage devices while maintaining manufacturing feasibility.
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 transistors with greater switching speed and reduced performance variation for a given leakage level, optimizing power dissipation and clock frequency without the drawbacks of doping, resulting in more efficient integrated circuit performance.
Implementation Method 1
The use of varying thicknesses of gate electrode material to modulate threshold voltages instead of doping, allowing for the creation of multi-threshold voltage devices with improved switching speed and reduced performance variation by altering the workfunction without affecting carrier mobility.
Data Source
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AI summary
Embodiments of the present disclosure describe multi-threshold voltage devices and associated techniques and configurations. In one embodiment, an apparatus includes a semiconductor substrate, a channel body disposed on the semiconductor substrate, a first gate electrode having a first thickness coupled with the channel body and a second gate electrode having a second thickness coupled with the channel body, wherein the first thickness is greater than the second thickness. Other embodiments may be described and/or claimed.