Semiconductor Heterostructure Epitaxial Growth via Circular Seed Openings
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Solution Overview
Problem
Existing semiconductor device manufacturing methods face challenges such as increased processing time and cost due to the need for seed island mesas with specific orientations, and dislocations occur where growth fronts meet between mesas.
Innovation Solution
A method involving a seed layer structure with circularly shaped openings is used, allowing for epitaxial growth without requiring specific mesa orientations, minimizing dislocations by growing the semiconductor layer mainly vertically and laterally into these openings, resulting in regions with significantly reduced defect densities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If seed island mesas are formed in a particular orientation with respect to the crystal direction of the semiconductor substrate, then the aspect ratio between the laterally grown third region and the vertical growth is maximized, but this adds processing time and costs to the manufacturing process
Solution Approach 1:
The invention segments the growth process into distinct phases: initial vertical growth from seed islands, followed by lateral overgrowth. This segmentation allows the seed islands to be formed without strict orientation requirements, while the subsequent lateral growth phase automatically achieves the desired aspect ratio and defect reduction, eliminating the need for precise initial orientation
Solution Approach 2:
The method performs preliminary vertical growth from the seed islands before the lateral overgrowth phase. This preliminary action establishes a foundation that enables the subsequent lateral growth to proceed with optimized aspect ratio and defect density, without requiring the seed islands to be precisely oriented beforehand
2Manufacturing precision
If seed island mesas are formed in a particular orientation with respect to the crystal direction of the semiconductor substrate, then the aspect ratio between the laterally grown third region and the vertical growth is maximized, but this increases manufacturing costs
Solution Approach 1:
The growth process is divided into vertical growth and lateral overgrowth phases, allowing standard photolithography to form seed islands without expensive orientation-controlled processes, while the lateral growth phase achieves the required precision automatically
Solution Approach 2:
The lateral overgrowth process self-adjusts to achieve optimal aspect ratio and defect density based on the geometry of the seed islands and growth conditions, eliminating the need for expensive precision orientation control during seed island formation
3Quantity of substance
If epitaxial growth occurs where growth fronts meet between two mesas, then semiconductor regions are formed, but dislocations occur in the epitaxially grown semiconductor layer in these regions
Solution Approach 1:
The invention creates different growth conditions in different regions: the central regions between mesas experience lateral overgrowth with low defect density, while the areas where growth fronts would meet are avoided or minimized through proper mesa spacing and geometry design
Solution Approach 2:
The use of circular mesas creates curved growth fronts that meet at points rather than along lines, significantly reducing the area where dislocations can form compared to rectangular mesas with straight edges that create extended dislocation lines
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 reduces processing complexity and costs by eliminating the need for precise mesa orientation and minimizes dislocations, achieving lower defect densities in the epitaxially grown semiconductor layers, enhancing the quality of semiconductor heterostructures.
Implementation Method 1
a semiconductor layer is epitaxially grown from the exposed at least portion of the seed layer structure, firstly mainly vertically and then into each of the one or more separated circularly shaped openings until the epitaxially grown semiconductor layer coalesces with the insulator layer or the semiconductor structure
Data Source
AI summary
This invention is directed toward a method for manufacturing a semiconductor device with a heterostructure comprises covering a semiconductor structure with a seed layer structure; forming one or more separated circularly shaped openings in the seed layer structure to expose the semiconductor structure therein, and leave the seed layer structure outside the one or more separated circularly shaped openings; forming an insulator layer thereon; etching the obtained structure to (i) expose at least a portion of the seed layer structure, such that the exposed at least portion of the seed layer structure surrounds each of the one or more separated circularly shaped openings, and (ii) optionally expose the semiconductor structure, in the one or more separated circularly shaped openings; and epitaxially growing a semiconductor layer from the exposed at least portion of the seed layer structure, firstly mainly vertically and then into each of the one or more separated circularly shaped openings until the epitaxially grown semiconductor layer coalesces with the insulator layer or the semiconductor structure in each of the one or more separated circularly shaped openings.