Vertical Semiconductor Pillar Device Trench Definition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Forming vertical devices such as thyristors or MOSFETs with vertical gates presents challenges, including poorly defined features due to simultaneous etching of multiple materials, which can lead to inaccuracies in trench formation and semiconductor structure creation.
Innovation Solution
Etching different materials at different times and forming a semiconductor structure partially between the etched materials, using silicon nitride and silicon dioxide as dielectrics, with epitaxial silicon growth self-aligned to the etched pillars, allowing for precise control and definition of features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple materials are etched simultaneously to form trenches, then the manufacturing process is simplified and productivity is improved, but the trench definition and feature precision deteriorate
Solution Approach 1:
The patent divides the etching process into separate sequential steps for different materials (silicon nitride etched first, then silicon dioxide etched afterward). This segmentation allows each material to be etched with optimized parameters and selective etchants, achieving well-defined trenches and features without the precision loss that would occur in simultaneous multi-material etching.
2Reliability
If epitaxial silicon is grown to form vertical pillars, then the device structure is improved, but the process complexity increases
Solution Approach 1:
The patent performs preliminary actions by first forming the complete dielectric structure (silicon nitride pillars and silicon dioxide trenches) before growing the epitaxial silicon. This preliminary structuring provides a well-defined template that guides the subsequent epitaxial growth, ensuring that silicon forms precisely where needed while maintaining process control and reducing overall complexity.
Solution Approach 2:
The epitaxial silicon growth is self-aligned to the existing silicon nitride pillars and silicon dioxide trenches. The pre-formed dielectric structures automatically serve as alignment references and physical constraints during epitaxial growth, eliminating the need for additional masking or alignment steps and reducing process complexity while ensuring high structural quality.
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 approach improves the precision and performance of vertical devices by enabling better-defined trench structures and epitaxial silicon growth, enhancing the formation of vertical thyristors or MOSFETs with improved performance compared to conventional methods.
Implementation Method 1
Etching different materials at different times and forming a semiconductor structure partially between the etched materials
Implementation Method 2
epitaxial silicon growth self-aligned to the etched pillars
Data Source
AI summary
Methods of fabricating vertical devices are described, along with apparatuses and systems that include them. In one such method, a vertical device is formed at least partially in a void in a first dielectric material and a second dielectric material. Additional embodiments are also described.