Bottom-Side Source-Drain Regrowth for Low Contact Resistance
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Solution Overview
Problem
Existing methods for forming contact structures in semiconductor devices result in high contact resistance due to thermal operations during back-end processing, leading to degraded device performance with increased power consumption and reduced switching speeds.
Innovation Solution
Amorphization and regrowth of source-drain regions from the bottom-side of a semiconductor assembly using implants followed by thermal annealing techniques, such as laser or rapid thermal annealing, to achieve a highly active metastable state of dopants, reducing contact resistance and improving device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If contact structures are formed in front-end processing operations, then contact structures are created during transistor fabrication, but thermal operations during back-end processing result in high contact resistance
Solution Approach 1:
The patent performs amorphization of source-drain regions before contact structure formation, creating a fresh amorphous surface that enables superior dopant activation. This preliminary action of amorphizing the semiconductor material prior to contact formation allows for optimized dopant diffusion and activation, achieving low contact resistance despite subsequent thermal processing during back-end operations.
Solution Approach 2:
The patent utilizes ion implantation to introduce dopants at controlled concentrations and depths into the amorphized source-drain regions. By changing the physical and chemical parameters of the semiconductor material through amorphization and controlled doping, the contact resistance is significantly reduced even after thermal annealing processes during back-end processing.
2Reliability
If high dopant activation is achieved adjacent to contact regions, then contact resistance is lowered, but device performance degrades with high power consumption and reduced switching speeds
Solution Approach 1:
The patent applies selective amorphization and doping to specific regions adjacent to contact structures, creating localized areas of high dopant activation only where needed for low contact resistance. This local quality enhancement ensures that high dopant concentration is achieved at the contact interface without adversely affecting the electrical characteristics of the channel and active regions, thereby maintaining fast switching speeds while reducing contact resistance.
Solution Approach 2:
The patent employs rapid thermal annealing processes to quickly activate dopants and restore crystalline structure in the source-drain regions after ion implantation. By rushing through the thermal processing step with controlled, rapid heating and cooling, the method achieves high dopant activation and low contact resistance while minimizing thermal exposure that could degrade device performance and switching characteristics.
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 process achieves significantly lower contact resistance, enabling increased drive current, faster switching speeds, and reduced power consumption in semiconductor devices.
Implementation Method 1
amorphization and regrowth of source-drain regions from the bottom-side of a semiconductor assembly using implants
Implementation Method 2
thermal annealing techniques, such as laser or rapid thermal annealing
Implementation Method 3
laser or rapid thermal annealing
Implementation Method 4
rapid thermal annealing
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
A device is disclosed. The device includes a channel, a first source-drain region adjacent a first portion of the channel, the first source-drain region including a first crystalline portion that includes a first region of metastable dopants , a second source-drain region adjacent a second portion of the channel, the second source-drain region including a second crystalline portion that includes a second region of metastable dopants. A gate conductor is on the channel.