Body Contact Dopant Diffusion Blocking Superlattice for Semiconductor Devices
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Solution Overview
Problem
Current semiconductor devices face limitations in achieving enhanced charge carrier mobility and reduced contact resistance due to existing materials and processing techniques.
Innovation Solution
The use of a body contact dopant diffusion blocking superlattice in semiconductor devices, comprising stacked groups of semiconductor and non-semiconductor monolayers, which divides the body contact into regions with varying conductivity and dopant concentrations, and includes a metal contact on the higher dopant concentration region to reduce Schottky barrier height and contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional body contact structure is used in semiconductor devices, then the device structure remains simple, but the contact resistance is high and charge carrier mobility is limited
Solution Approach 1:
The body contact structure is segmented into multiple regions with different dopant concentrations by introducing a superlattice barrier layer that divides the contact into a first region with lower dopant concentration and a second region with higher dopant concentration. This segmentation allows optimization of both contact resistance and charge carrier mobility by having different doping levels in different regions.
Solution Approach 2:
Different regions of the body contact are assigned different dopant concentrations to optimize local properties. The first region has lower dopant concentration to maintain charge carrier mobility, while the second region has higher dopant concentration to reduce contact resistance. This local quality differentiation resolves the contradiction between contact resistance and mobility.
2Reliability
If high dopant concentration is used in the body contact to reduce contact resistance, then contact resistance decreases, but dopant diffusion into the channel region increases
Solution Approach 1:
A superlattice barrier layer is introduced as an intermediary between the high dopant concentration region and the channel region. This barrier layer prevents dopant diffusion into the channel while allowing the high dopant concentration region to maintain low contact resistance. The barrier layer acts as a mediator that decouples the relationship between dopant concentration and diffusion.
Solution Approach 2:
The body contact is segmented into regions with different dopant concentrations, with a barrier layer separating the high dopant concentration region from the channel. This segmentation allows the high dopant concentration to be localized in the contact region without causing diffusion into the channel, thus maintaining both low contact resistance and stable dopant distribution.
3Speed
If strained material layers are used to enhance charge carrier mobility, then mobility increases, but the device structure and manufacturing process become more complex
Solution Approach 1:
The patent modifies the dopant concentration parameter in different regions of the body contact rather than changing material composition or introducing strained layers. By adjusting dopant concentration locally, the patent achieves improved charge carrier mobility without the structural complexity and manufacturing challenges associated with strained material layers.
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 configuration enhances charge carrier mobility by reducing effective mass and contact resistance, while also acting as a barrier to dopant diffusion, improving device performance and mobility.
Implementation Method 1
body contact dopant diffusion blocking superlattice
Implementation Method 2
reduce Schottky barrier height and contact resistance
Data Source
AI summary
A method for making a semiconductor device may include forming spaced apart source and drain regions in a semiconductor layer with a channel region extending therebetween, and forming a gate on the channel region. The method may further include forming a body contact in the semiconductor layer and including a body contact dopant diffusion blocking superlattice extending through the body contact to divide the body contact into a first body contact region and an second body contact region with the second body contact region having a same conductivity and higher dopant concentration than the first body contact region. The body contact dopant diffusion blocking superlattice may include a respective plurality of stacked groups of layers, with each group of layers including a plurality of stacked base semiconductor monolayers defining a base semiconductor portion, and at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent base semiconductor portions.