2D Material Transistor Contacts for Short-Channel Mobility
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Solution Overview
Problem
The challenge in semiconductor device design is to reduce transistor size while maintaining performance, particularly addressing the short channel effect that lowers carrier mobility, which conventional silicon materials face when channel length is shortened.
Innovation Solution
The use of a semiconductor device architecture that incorporates a two-dimensional material layer with a specific source/drain contact structure, where the source/drain contact has varying widths and aspect ratios to enhance contact area and reduce resistance, is proposed. This architecture includes a substrate with two-dimensional material layers and gate structures, with source/drain contacts surrounding the material layers to improve contact efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the channel length of the transistor is shortened to reduce device size, then integration density is improved, but carrier mobility deteriorates due to short channel effect
Solution Approach 1:
The patent changes the material parameter from conventional silicon to two-dimensional materials (such as TMDs), which fundamentally alters the electrical characteristics and enables maintaining high carrier mobility even at shortened channel lengths, thus resolving the short channel effect problem
Solution Approach 2:
The patent employs composite material structures including two-dimensional material layers combined with specific contact structures (first portion and second portion with different aspect ratios), creating a composite system that optimizes both size and performance characteristics
2Ease of manufacture
If conventional silicon material is used in short channel transistors, then manufacturing simplicity is maintained, but performance deteriorates due to lowered carrier mobility
Solution Approach 1:
The patent changes the fundamental material parameter from silicon to two-dimensional materials, transforming the electrical properties to achieve high carrier mobility while accepting the need for specialized fabrication processes for these new materials
3Reliability
If the contact area between source/drain contact and two-dimensional material layer is increased, then resistance is reduced, but device complexity increases due to multi-portion contact structure
Solution Approach 1:
The contact structure is segmented into multiple portions (first portion and second portion) with different aspect ratios, where each portion serves a specific function: the first portion provides initial contact while the second portion with larger aspect ratio enhances the contact area and reduces resistance
Solution Approach 2:
Different portions of the contact structure have different local qualities (aspect ratios), with the second portion having a larger aspect ratio specifically designed to maximize contact area with the two-dimensional material layer, optimizing electrical connection at the critical contact interface
Data Source
AI summary
A semiconductor device includes a substrate, a two-dimensional material layer on the substrate, the two-dimensional material layer extending in a first direction, a gate structure extending in a second direction intersecting the first direction, the gate structure on the two-dimensional material layer, and a source/drain contact on the substrate. The source/drain contact surrounds each opposing end of the two-dimensional material layer, the source/drain contact includes a first portion in contact with each opposing end of the two-dimensional material layer, the source/drain contact includes a second portion on the first portion, and the second portion has a larger aspect ratio than an aspect ratio of the first portion.