Lateral Epitaxial Semiconductor Layers for Long-Range Crystallization
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Solution Overview
Problem
Conventional lateral solid-phase epitaxy processes are limited by the effective distance for crystallization in a horizontal direction over a dielectric layer, restricting the growth of single-crystal semiconductor materials.
Innovation Solution
A structure comprising a first semiconductor layer with adjacent sections and a second semiconductor layer that projects from the first layer, separated by a dielectric layer, where lateral solid-phase epitaxy is used to convert amorphous semiconductor materials to single-crystal materials, extending the crystallization distance beyond conventional limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If conventional lateral solid-phase epitaxy processes are used, then crystallization can occur, but the effective distance for crystallization in the horizontal direction is limited
Solution Approach 1:
The patent segments the crystallization process into two distinct stages: first forming an amorphous semiconductor layer that extends beyond the dielectric layer, then performing lateral solid-phase epitaxy to convert it to single-crystal material. This segmentation allows the crystallization front to propagate further laterally than conventional processes, achieving extended crystallization distance while maintaining crystal quality.
Solution Approach 2:
The patent performs preliminary deposition of amorphous semiconductor material beyond the dielectric layer edges before initiating lateral solid-phase epitaxy. This preliminary action creates a reservoir of amorphous material that enables the crystallization front to travel further laterally, effectively extending the crystallization distance without compromising the single-crystal quality of the final product.
2Length of stationary object
If lateral solid-phase epitaxy is extended beyond conventional limits, then longer crystallization distance is achieved, but process complexity increases
Solution Approach 1:
The patent utilizes parameter changes in the deposition and annealing processes to achieve extended lateral crystallization. By controlling deposition temperature, rate, and subsequent annealing conditions, the process extends crystallization distance through standard equipment operations rather than introducing fundamentally new process steps, thereby limiting the increase in process complexity.
3Length of stationary object
If amorphous semiconductor material is deposited beyond dielectric layer edges, then lateral crystallization distance is extended, but manufacturing precision requirements increase
Solution Approach 1:
The patent uses the dielectric layer as an intermediary structure that defines the initial deposition region. The amorphous semiconductor material is deposited to extend beyond this intermediary, and the lateral solid-phase epitaxy process uses the dielectric layer edges as a reference for controlled crystallization propagation, managing alignment precision through the intermediary's geometric definition.
Solution Approach 2:
The patent segments the semiconductor layer into regions with different crystalline states: amorphous regions deposited beyond the dielectric layer and single-crystal regions formed through lateral epitaxy. This segmentation allows different precision requirements for different regions, with the amorphous region serving as a tolerance-absorbing buffer that reduces overall alignment precision demands.
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 method enables long-range crystallization of semiconductor materials over dielectric layers, forming seamless semiconductor layers with reduced defects, suitable for advanced device structures like electro-optical modulators.
Implementation Method 1
Solid-phase epitaxy refers to the type of growth when a semiconductor material undergoes a transition from an amorphous phase to a single-crystal phase. Lateral solid-phase epitaxy involves the formation of an epitaxial semiconductor material over a dielectric layer.
Data Source
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AI summary
Structures that include a semiconductor layer formed by lateral epitaxial growth and methods of forming such structures. The structure comprises a first semiconductor layer including a first section and a second section adjacent to the first section, a second semiconductor layer including a section and a semiconductor region that projects from the second section of the first semiconductor layer to the section of the second semiconductor layer, and a dielectric layer disposed between the first section of the first semiconductor layer and the section of the second semiconductor layer. The section and the semiconductor region of the second semiconductor layer comprise one or more single-crystal semiconductor materials.