2D Semiconductor Contact Structure for Stable Ohmic Interfaces
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Solution Overview
Problem
The challenge of achieving stable ohmic contact between two-dimensional materials and metals in semiconductor devices, particularly in field-effect transistors, is hindered by high contact resistance and susceptibility to oxidation, which existing methods like hydrogen or helium plasma treatment and graphene insertion face compatibility and stability issues.
Innovation Solution
A semiconductor device is fabricated by forming a two-dimensional semiconductor layer with a two-dimensional metal conductor layer and a metal layer, where cations from the metal layer bond with anions from the semiconductor layer at controlled temperatures, forming a two-dimensional metal conductor layer that reduces contact resistance and avoids oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrogen or helium plasma is used to treat the surface of two-dimensional materials, then the contact resistance is reduced, but the surface stability deteriorates and oxidation occurs
Solution Approach 1:
The patent introduces a two-dimensional metal conductor layer as an intermediary between the metal contact layer and the two-dimensional semiconductor layer. This intermediate layer mediates the interaction, enabling low contact resistance through cation-anion bonding while protecting the semiconductor surface from oxidation and plasma damage.
Solution Approach 2:
The patent changes the physical and chemical parameters of the interface by forming a two-dimensional metal conductor layer with specific formation energy characteristics. This parameter change enables the system to achieve low contact resistance through ionic bonding mechanisms while maintaining surface stability.
2Reliability
If graphene is inserted between metal and two-dimensional semiconductor, then the Schottky barrier is reduced, but the manufacturing process complexity increases due to incompatibility with CMOS processes
Solution Approach 1:
The patent changes the material parameters by selecting two-dimensional metal materials with formation energies lower than the semiconductor material, enabling thermodynamically stable ionic bonding. This parameter change achieves Schottky barrier reduction while maintaining compatibility with standard CMOS manufacturing processes through annealing treatment.
3Loss of energy
If two-dimensional materials are used in the channel, then the leakage current is reduced, but the contact resistance with metal increases
Solution Approach 1:
The patent introduces a two-dimensional metal conductor layer as an intermediary that bridges the metal contact and the two-dimensional semiconductor channel. This intermediate layer enables efficient charge transport at the contact interface through cation-anion bonding, reducing contact resistance while preserving the low leakage current properties of the bulk two-dimensional semiconductor material.
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 method effectively reduces contact resistance and ensures stable ohmic contact, enabling the successful application of two-dimensional materials in semiconductor devices, particularly field-effect transistors, while being compatible with CMOS manufacturing processes.
Implementation Method 1
The two-dimensional metal conductor layer is formed by bonding of cations from the metal layer and anions from the two-dimensional semiconductor layer
Implementation Method 2
annealing in a controlled atmosphere at a temperature ranging from 600° C. to 1000° C. to enable that metal cations from the metal layer and anions from the two-dimensional semiconductor layer are bonded
Data Source
AI summary
A semiconductor device includes a two-dimensional semiconductor layer formed by a two-dimensional semiconductor material having a first formation energy, a two-dimensional metal conductor layer formed by a two-dimensional metal material and covering a surface of the two-dimensional semiconductor layer, and a metal layer covering a surface of the two-dimensional metal conductor layer. The two-dimensional metal material has a second formation energy smaller than the first formation energy. The two-dimensional metal conductor layer is formed by bonding of cations from the metal layer and anions from the two-dimensional semiconductor layer. As such, the contact resistances between the two-dimensional materials and the metals can be effectively reduced, enabling the application of the two-dimensional materials in semiconductor devices such as field-effect transistors.