2D Semiconductor Contact Structure With Energy-Band Alignment Layer
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Solution Overview
Problem
The scaling of semiconductor devices is limited by the difficulty in forming thin silicon channels while maintaining crystallinity, and there is a need to reduce contact resistance between two-dimensional material layers and conductive layers in transistors.
Innovation Solution
A semiconductor device structure is introduced that includes a two-dimensional material layer with a conductive layer and an alignment adjusting layer, which adjusts the energy-band alignment between the two-dimensional material layer and the conductive layer, using materials like RuCl3, NbS2, and WO3 to provide holes or electrons, thereby reducing contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicon is used as a channel layer and over-doped regions are formed to reduce contact resistance, then contact resistance is reduced, but the silicon cannot be formed thin while maintaining crystallinity, limiting scaling
Solution Approach 1:
The patent changes the material parameter from conventional silicon to two-dimensional materials (such as transition metal dichalcogenides), which have fundamentally different physical properties. This material substitution enables the channel to be formed with atomic-layer thinness (1-3 nm) while maintaining crystallinity and semiconductor characteristics, resolving the scaling limitation of silicon-based channels
Solution Approach 2:
The patent introduces an alignment adjusting layer as an intermediary between the two-dimensional material channel and the conductive layer. This intermediate layer, with specific work function values, mediates the energy-band alignment at the interface, enabling effective control of carrier injection and reduction of contact resistance in ultrathin two-dimensional material channels
2Length of moving object
If two-dimensional materials are used as channel layers to enable scaling, then channel thickness is reduced, but contact resistance between the two-dimensional material layer and conductive layer needs to be reduced
Solution Approach 1:
The patent adjusts the work function parameter of the alignment adjusting layer to match or exceed the ionization energy of the two-dimensional material (work function ≥ ionization energy). This parameter optimization enables effective hole injection and reduces contact resistance at the conductive layer-two-dimensional material interface, solving the contact resistance issue in ultrathin channels
Solution Approach 2:
The alignment adjusting layer serves as a mediator that bridges the conductive layer and two-dimensional material channel. By controlling its work function and thickness (equal to or less than the two-dimensional material layer thickness), it facilitates carrier transport across the interface while maintaining the ultrathin channel structure
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 structure effectively reduces contact resistance and allows for the scaling of semiconductor devices by controlling the energy-band alignment, enabling the use of two-dimensional materials as channel layers in transistors, facilitating the production of both n-type and p-type transistors for improved logic circuit efficiency.
Implementation Method 1
The alignment adjusting layer may adjust an energy-band alignment between the 2D material layer and the conductive layer
Implementation Method 2
a work function of the alignment adjusting layer may be greater than an ionization energy of the 2D material layer
Implementation Method 3
a work function of the alignment adjusting layer may be less than an electron affinity of the 2D material layer
Data Source
AI summary
A semiconductor device may include a two-dimensional (2D) material having a semiconductor characteristic, a conductive layer on a first surface of the 2D material layer, and an alignment adjusting layer on a second surface of the 2D material layer. The second surface may be different from the first surface. The alignment adjusting layer may adjust an energy-band alignment between the 2D material layer and the conductive layer.