Semiconductor Source/Drain Contact Structure With 2D Diffusion Barrier
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Solution Overview
Problem
As transistors in integrated circuit devices become smaller, there is a challenge in preventing gases or metals used for forming source/drain electrodes from diffusing into surrounding layers, which affects the performance and reliability of the devices.
Innovation Solution
Incorporating a conductive two-dimensional material as a barrier between the silicide film and the electrode, with a thickness ranging from 0.3 nm to 2 nm, to limit diffusion and maintain low resistance, while using a silicide film made of silicon and metals like W, Ti, Co, or Ni to reduce contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the transistor size is reduced to increase integration density, then the device area is reduced, but diffusion of gases or metals into surrounding layers occurs
Solution Approach 1:
A conductive barrier layer comprising a conductive two-dimensional material is introduced between the source/drain electrode and the surrounding layers. This intermediary layer prevents diffusion of gases or metals into the channel and gate insulating film while maintaining electrical conductivity, thus resolving the contradiction between miniaturization and diffusion prevention.
Solution Approach 2:
The source/drain structure employs a composite configuration combining the conductive two-dimensional material barrier layer with conventional conductive materials. This composite structure achieves both diffusion barrier functionality and electrical conductivity, enabling reduced transistor size without compromising reliability.
2Reliability
If a thick barrier layer is used to prevent diffusion, then diffusion prevention is improved, but contact resistance increases
Solution Approach 1:
The conductive two-dimensional material barrier layer is designed with ultrathin thickness (single layer or few layers) to maintain low contact resistance while providing effective diffusion barrier. The atomic-scale thickness parameter optimization allows the barrier to be sufficiently thin for good electrical contact yet sufficiently dense to prevent diffusion.
Solution Approach 2:
The conductive two-dimensional material serves as an intermediary that simultaneously provides diffusion barrier and electrical conduction pathways. Its unique atomic structure allows it to function as both a protective barrier and a conductive medium, resolving the trade-off between barrier thickness and contact resistance.
3Reliability
If conventional barrier materials are used, then diffusion prevention is achieved, but device complexity increases
Solution Approach 1:
The conductive two-dimensional material is integrated as a single atomic-layer intermediary between the electrode and surrounding structures. This monolayer approach provides diffusion barrier functionality without adding significant structural complexity, as it can be deposited as a single thin layer rather than requiring multiple thick barrier layers.
Solution Approach 2:
The patent replaces conventional thick physical barrier structures with an atomic-scale two-dimensional material barrier. This substitution reduces the physical thickness and structural complexity while maintaining or improving the barrier effectiveness through the unique properties of two-dimensional materials.
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 solution enables the miniaturization of semiconductor devices while maintaining high performance by preventing diffusion and reducing contact resistance, thus enhancing the reliability and efficiency of the transistors.
Implementation Method 1
a conductive barrier between the silicide film and the electrode. The conductive barrier may include a conductive two-dimensional material
Implementation Method 2
The silicide film may be a mixture of silicon and at least one of W, Ti, Co, Ni, Pt, and an alloy thereof
Data Source
AI summary
A semiconductor device includes a first source/drain structure including a first semiconductor region and a first electrode in electrical contact with the first semiconductor region; a second source/drain structure including a second semiconductor region and a second electrode in electrical contact with the second semiconductor region; a channel between the first semiconductor region and the second semiconductor region; and a gate structure including a gate insulating film covering the channel and a gate electrode covering the gate insulating film. The first source/drain structure further includes a silicide film between the first semiconductor region and the first electrode and a conductive barrier between the silicide film and the first electrode. The conductive barrier includes a conductive two-dimensional material.