Vertical III-V Electrode Structure Without Lattice Relaxation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The formation of group III-V semiconductor devices on silicon substrates is complex and results in relaxation of the strained lattice constant, leading to dislocations and reduced performance, particularly in high-power applications due to the need for complex processes that relax the lattice constant to form bottom electrodes.
Innovation Solution
A semiconductor structure with a bottom electrode extending along the sidewalls of pillars within the buffer layer and silicon substrate, maintaining the strained lattice constant of the active layer and preventing dislocations, thereby enhancing device performance and simplifying the fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If complex processes are used to relax the lattice constant to form bottom electrodes, then device fabrication can proceed, but the manufacturing complexity increases and device performance decreases due to dislocations
Solution Approach 1:
The substrate structure is segmented into multiple pillars arranged in an array, with openings between them. This segmentation allows the bottom electrode to be formed without requiring lattice constant relaxation, eliminating dislocations while maintaining manufacturing feasibility. The pillar structure divides the continuous substrate into discrete regions that can be processed independently.
Solution Approach 2:
The buffer layer serves as an intermediary between the silicon substrate and the active layer. It provides a transition structure that maintains the strained lattice constant of the active layer while allowing the bottom electrode to be formed through the pillar structures. This intermediary layer prevents direct contact that would cause dislocation propagation.
2Ease of manufacture
If the lattice constant is relaxed to form bottom electrodes, then electrode formation is enabled, but dislocations are generated reducing breakdown voltage
Solution Approach 1:
By segmenting the substrate into pillars with openings, the patent enables bottom electrode formation through the openings without requiring lattice constant relaxation. This segmentation approach maintains the strained lattice structure intact, preventing dislocation generation while still allowing electrical contact to the active layer.
Solution Approach 2:
The pillar structures create localized regions where the bottom electrode can contact the active layer through the openings, while the rest of the structure maintains the strained lattice constant. This local quality approach allows electrode formation only where needed (through openings) without compromising the overall lattice strain and breakdown voltage performance.
3Productivity
If conventional electrode formation processes are used, then manufacturing can proceed, but the active layer experiences strain relaxation leading to dislocations
Solution Approach 1:
The pillar array structure segments the substrate in a way that allows conventional manufacturing processes to proceed without disrupting the lattice strain. The openings between pillars provide access for electrode formation while the pillar structures themselves maintain the strained lattice constant, achieving both manufacturing throughput and manufacturing precision.
Data Source
AI summary
Various embodiments of the present disclosure are directed towards a method for forming a semiconductor structure, the method includes forming a buffer layer over a substrate. An active layer is formed on the buffer layer. A top electrode is formed on the active layer. An etch process is performed on the buffer layer and the substrate to define a plurality of pillar structures. The plurality of pillar structures include a first pillar structure laterally offset from a second pillar structure. At least portions of the first and second pillar structures are spaced laterally between sidewalls of the top electrode.