2D Semiconductor Gate Stack for Threshold Voltage Control
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Solution Overview
Problem
The miniaturization of transistors in integrated circuit devices poses challenges in maintaining desired electrical capabilities due to the shortening of channel length and thickness, leading to issues such as the short channel effect, which complicates the formation of a stable gate insulating film and affects the threshold voltage.
Innovation Solution
A semiconductor device is designed with a two-dimensional channel made of transition metal dichalcogenide material, surrounded by a transition metal oxide layer and a high-k dielectric layer, which have different oxygen densities, creating electric dipole moments that adjust the Fermi energy level and work function of the gate electrode, thereby enabling the adjustment of threshold voltage and maintaining performance despite reduced channel dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the channel length and layer thickness are reduced to improve transistor integration, then the device size is reduced, but the short channel effect increases and threshold voltage control becomes difficult
Solution Approach 1:
The patent changes the material composition of the gate insulating film by incorporating transition metal oxide layers with specific oxygen deficiencies. This material parameter change enables effective threshold voltage control in miniaturized transistors by creating electric dipole moments that compensate for short channel effects, thus resolving the contradiction between reduced device size and maintained reliability
Solution Approach 2:
The gate insulating film is constructed as a composite structure combining high-k dielectric materials with transition metal oxide layers. This composite material approach provides both the electrical insulation properties needed for miniaturization and the oxygen deficiency-induced dipole moments required for threshold voltage control, simultaneously addressing both requirements
2Productivity
If the channel length is shortened to increase integration density, then more transistors can be packed, but the formation of stable gate insulating film becomes complicated
Solution Approach 1:
The patent modifies the oxygen content parameter in the gate insulating film by introducing transition metal oxide layers with controlled oxygen deficiencies. This parameter change simplifies the manufacturing process by providing a systematic method to achieve the required electrical properties in miniaturized devices without complex process adjustments
Solution Approach 2:
The transition metal oxide layer acts as an intermediary between the channel and the gate electrode, mediating the electrical interaction through oxygen deficiency-induced dipole moments. This intermediary structure simplifies the overall device fabrication by decoupling the requirements for electrical performance and physical 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 configuration allows for the miniaturization of semiconductor devices while maintaining desired operational capabilities, including adjustable threshold voltages, which is beneficial for high integration and logic design, and reduces the impact of short channel effects.
Implementation Method 1
The transition metal oxide layer and the dielectric layer may have different oxygen densities... creating electric dipole moments that adjust the Fermi energy level and work function of the gate electrode
Data Source
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AI summary
A semiconductor device includes a channel including a two-dimensional (2D) semiconductor material, a source electrode and a drain electrode electrically connected to opposite sides of the channel, respectively, a transition metal oxide layer on the channel and including a transition metal oxide, a dielectric layer on the transition metal oxide layer and including a high-k material, and a gate electrode on the dielectric layer.