III-N Vertical Component Platelets With Low-Dislocation Epitaxy
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Solution Overview
Problem
The production of vertical microelectronic components based on III-N materials, such as gallium nitride (GaN), faces challenges due to high dislocation densities and complex, costly processes, particularly in achieving high-quality epitaxial growth without the defects introduced by traditional etching methods.
Innovation Solution
A method involving a stack of pads with a crystalline and creeping section, where epitaxial growth of III-N material forms platelets without coalescence defects, eliminating the need for etching and using a 'bottom-up' approach to produce high-quality, low-dislocation GaN platelets suitable for power components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional etching methods are used to produce vertical components, then device structure can be formed, but dislocation densities increase and manufacturing complexity increases
Solution Approach 1:
The patent inverts the conventional top-down etching approach by using a bottom-up self-assembly method. Instead of starting with a continuous layer and removing material to form pads, the invention grows crystallites from discrete seed pads that automatically coalesce to form the desired structure, eliminating etching steps and reducing dislocation densities.
Solution Approach 2:
The patent performs preliminary action by pre-forming discrete seed pads with specific crystal orientations before the epitaxial growth step. These pre-prepared seed pads serve as controlled nucleation sites that guide the subsequent crystallite growth and coalescence, ensuring low dislocation densities in the final structure.
2Stability of the object's composition
If epitaxial growth is continued until complete coalescence of crystallites, then continuous layer is formed, but coalescence defects are introduced
Solution Approach 1:
The patent applies partial action by controlling the epitaxial growth process to achieve coalescence of crystallites from adjacent pads while deliberately avoiding excessive growth that would cause defects. The growth is stopped at the optimal point where continuity is achieved without introducing coalescence defects, demonstrating precise process control.
3Ease of manufacture
If GaN is grown on Si or SiC substrates, then production cost is reduced, but dislocation densities become too high for vertical power transistors
Solution Approach 1:
The patent applies segmentation by dividing the continuous epitaxial layer into discrete crystallites that grow from separated seed pads. This segmentation allows each crystallite to develop with low dislocation density from its own nucleation site, and the final coalesced structure maintains these low defect levels while being grown on cost-effective Si or SiC substrates.
4Strength
If vertical component thickness is increased to improve withstand voltage, then power density increases, but manufacturing complexity increases
Solution Approach 1:
The patent ensures continuity of useful action by maintaining low dislocation densities throughout the entire thickness of the GaN layer during epitaxial growth. The bottom-up approach allows continuous growth of high-quality material from the substrate interface to the surface, enabling thick layers with improved withstand voltage without introducing defects that would compromise manufacturing simplicity.
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 method significantly reduces dislocation densities, enables high thicknesses, and simplifies the production of vertical components with improved performance and reduced costs, suitable for power transistors and other microelectronic devices.
Implementation Method 1
epitaxially growing a crystallite made of III-N material on at least some of the tops of said pads and continuing the epitaxial growth of the crystallites until coalescence of the crystallites carried by the adjacent pads of one same assembly
Implementation Method 2
the phenomenon of plastic creep of the sections formed by the pads at the epitaxial temperature makes it possible to reduce the dislocation densities
Implementation Method 3
a crystalline section, a creeping section, formed of a material having a vitreous transition temperature Tvitreous transition, the crystalline section surmounting the creeping section
Data Source
AI summary
A method for producing a vertical component comprising with the basis of a III-N material, comprising providing platelets made of the III-N material obtained by epitaxy on pads, the platelets comprise at least first and second layers doped and stacked on one another in a vertical direction. The method further includes the production of a first electrode and the production of a second electrode located on the platelet and configured such that a current passing from one electrode to the other passes through at least the second layer in all of its thickness, the thickness being taken in the vertical direction.