RF Ground Plane Superlattice for Mobility and Breakdown Control
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Solution Overview
Problem
Existing semiconductor devices face challenges in enhancing charge carrier mobility and performance, particularly in radio frequency (RF) applications, where breakdown mechanisms and dopant diffusion limit device efficiency.
Innovation Solution
Incorporating a conductive superlattice layer with alternating doped semiconductor and non-semiconductor monolayers, such as Si/O, to form a highly doped ground plane that reduces scattering and dopant diffusion, while maintaining a common energy band structure for improved mobility and breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a highly doped ground plane is used to reduce scattering and improve mobility, then charge carrier mobility is enhanced, but dopant diffusion increases causing performance degradation
Solution Approach 1:
The ground plane is segmented into alternating monolayers of semiconductor material (e.g., silicon) and non-semiconductor material (e.g., oxygen). This segmentation creates discrete dopant confinement zones that prevent dopant diffusion while maintaining high doping concentrations in the semiconductor layers, thus enhancing mobility without the harmful effects of dopant spreading.
Solution Approach 2:
The non-semiconductor monolayers (e.g., oxygen layers) act as intermediary barrier layers between doped semiconductor regions. These intermediary layers physically block dopant diffusion while allowing the semiconductor layers to maintain high carrier concentrations, effectively mediating between the need for high doping and the need to prevent dopant loss.
2Speed
If the semiconductor layer thickness is reduced to improve switching speed, then switching speed increases, but breakdown voltage decreases
Solution Approach 1:
The ground plane is constructed as a composite material structure with alternating semiconductor and non-semiconductor monolayers. This composite structure enables the semiconductor layers to be made thinner for faster switching while the non-semiconductor layers provide additional breakdown protection, allowing the device to achieve high switching speed without sacrificing breakdown voltage.
3Reliability
If alternating semiconductor and non-semiconductor monolayers are used to form a superlattice, then charge carrier mobility is enhanced through reduced scattering, but device complexity increases
Solution Approach 1:
The invention changes the structural parameters of the ground plane by introducing alternating monolayers with different material compositions. This parameter change creates a superlattice structure that reduces scattering and enhances mobility. While the structure becomes more complex, the use of standard semiconductor materials and conventional fabrication techniques keeps the complexity manageable.
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 superlattice layer enhances charge carrier mobility, reduces unwanted scattering, and improves breakdown voltage, enabling thinner semiconductor-on-insulator devices with faster switching and lower resistance, thus advancing RF semiconductor performance.
Implementation Method 1
The superlattice layer enhances charge carrier mobility, reduces unwanted scattering
Implementation Method 2
at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent doped base semiconductor portions
Data Source
AI summary
A radio frequency (RF) semiconductor device may include a semiconductor-on-insulator substrate, and an RF ground plane layer on the semiconductor-on-insulator substrate including a conductive superlattice. The conductive superlattice may include stacked groups of layers, with each group of layers comprising stacked doped base semiconductor monolayers defining a doped base semiconductor portion, and at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent doped base semiconductor portions. The RF semiconductor device may further include a body above the RF ground plane layer, spaced apart source and drain regions adjacent the body and defining a channel region in the body, and a gate overlying the channel region.