2D Crystal Contact Structure for Low-Resistivity Semiconductor Interfaces
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Solution Overview
Problem
Existing semiconductor devices face challenges in reducing contact resistivity due to the limitations of lowering the Schottky energy barrier and increasing doping concentration, which affects the performance of smaller semiconductor devices.
Innovation Solution
A semiconductor device is designed with a two-dimensional (2D) material layer and a metal compound layer between the metal and semiconductor layers, where the metal compound layer has a higher reaction energy with oxygen than the semiconductor, inhibiting the formation of a semiconductor oxide and reducing contact resistivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal layer is directly formed on a semiconductor layer to reduce contact resistance, then electrical conductivity is improved, but a Schottky barrier forms due to hetero-junction between metal and semiconductor
Solution Approach 1:
A 2D material layer is introduced as an intermediary between the metal layer and semiconductor layer. This 2D material serves as a mediator that enables direct contact between metal and semiconductor without forming a Schottky barrier, thereby reducing contact resistivity while maintaining low resistance electrical connection.
Solution Approach 2:
The patent employs a composite structure consisting of multiple layers: metal layer, 2D material layer, and semiconductor layer. This composite material approach combines the advantages of each material - the conductivity of metal, the barrier-free interface properties of 2D material, and the semiconductor functionality - to achieve low contact resistivity without Schottky barrier formation.
2Reliability
If the work function of metal is adjusted to lower the Schottky energy barrier, then contact resistivity is reduced, but the work function becomes pinned on the semiconductor surface limiting further reduction
Solution Approach 1:
The 2D material layer acts as an intermediary that decouples the metal work function from the semiconductor surface effects. By inserting this intermediate layer, the metal's work function is no longer pinned by the semiconductor surface, allowing for broader adjustment range and optimized contact properties.
3Reliability
If doping concentration of semiconductor surface is increased to reduce depletion width, then contact resistivity is reduced, but stability of doped state becomes difficult to maintain in smaller devices
Solution Approach 1:
The 2D material layer serves as an intermediary that eliminates the need for high doping concentration at the semiconductor surface. By providing a direct contact interface through the 2D material, the depletion width issue is resolved without requiring unstable high doping levels, thereby maintaining doped state stability even in smaller devices.
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
The inclusion of a 2D material layer and a metal compound layer significantly reduces contact resistivity, enhancing the electrical characteristics and stability of the semiconductor device, even at higher doping concentrations, by preventing oxide formation and maintaining low resistance.
Implementation Method 1
A reaction energy between a metal included in the metal compound layer and oxygen may be greater than a reaction energy between a semiconductor included in the semiconductor layer and oxygen
Data Source
AI summary
A semiconductor device is provided. The semiconductor device includes a metal layer, a semiconductor layer in electrical contact with the metal layer, a two-dimensional (2D) material layer disposed between the metal layer and the semiconductor layer and having a 2D crystal structure, and a metal compound layer disposed between the 2D material layer and the semiconductor layer.