HVPE Heteroepitaxy With Graded Buffer Layers for Thick Semiconductor Growth
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current heteroepitaxial growth techniques face challenges in achieving thick, high-quality layers due to lattice and thermal mismatches, leading to issues like layer cracking and poor domain fidelity, especially when using non-native substrates, which limits the development of advanced optoelectronic and solar cell technologies.
Innovation Solution
An in-situ pre-growth treatment of the substrate using non-native precursors to form a graded buffer layer, allowing for a smooth transition between the substrate and the growing layer, thereby reducing strain and improving layer quality, as demonstrated in the one-step thick HVPE growth process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If heteroepitaxial growth is performed directly on non-native substrates, then substrate cost is reduced and material availability is improved, but layer quality deteriorates due to lattice and thermal mismatches causing cracking and poor domain fidelity
Solution Approach 1:
The patent applies preliminary action by performing in-situ pre-growth treatment of the substrate before the main heteroepitaxial growth. This treatment modifies the substrate surface to create a graded buffer layer that gradually transitions between the substrate and the growing layer, thereby reducing strain accumulation and preventing cracking while maintaining the benefits of non-native substrates
Solution Approach 2:
The patent introduces an intermediary graded buffer layer formed through in-situ pre-growth treatment. This buffer layer acts as a mediator between the non-native substrate and the growing semiconductor layer, gradually accommodating the lattice and thermal mismatches to prevent layer cracking and improve domain fidelity
2Length of moving object
If thick heteroepitaxial layers are grown to achieve desired thickness, then device functionality is improved, but layer quality deteriorates due to strain accumulation causing cracking and defects
Solution Approach 1:
The in-situ pre-growth treatment is performed before the main thick layer growth to prepare the substrate surface. This preliminary action creates a graded buffer layer that can accommodate strain during subsequent thick layer growth, enabling the formation of hundreds of microns thick layers without cracking or defects
Solution Approach 2:
The patent changes the growth parameters during the in-situ pre-growth treatment to form a graded buffer layer with gradually varying composition. This parameter change allows the buffer layer to progressively accommodate strain, enabling thick layer growth while maintaining layer integrity and preventing cracking
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 enables the growth of high-quality, thick heteroepitaxial layers with excellent domain fidelity, overcoming traditional limitations and facilitating the development of advanced optoelectronic and solar cell technologies by improving the accommodation of growing layers to foreign substrates.
Implementation Method 1
Heteroepitaxy, i.e. the growth of one material on a substrate from another material
Implementation Method 2
Hydride Vapor Phase Epitaxy (HVPE) technique
Data Source
AI summary
A method of performing HVPE heteroepitaxy comprises exposing a substrate to a carrier gas, a first precursor gas, a Group II/III element, and ternary-forming gasses (V/VI group precursor), to form a heteroepitaxial growth of a binary, ternary, and/or quaternary compound on the substrate; wherein the carrier gas is H2, wherein the first precursor gas is HCl, the Group II/III element comprises at least one of Zn, Cd, Hg, Al, Ga, and In; and wherein the ternary-forming gasses comprise at least two or more of AsH3 (arsine), PH3 (phosphine), H2Se (hydrogen selenide), H2Te (hydrogen telluride), SbH3 (hydrogen antimonide, or antimony tri-hydride, or stibine), H2S (hydrogen sulfide), NH3 (ammonia), and HF (hydrogen fluoride); flowing the carrier gas over the Group II/III element; exposing the substrate to the ternary-forming gasses in a predetermined ratio of first ternary-forming gas to second ternary-forming gas (1tf:2tf ratio); and changing the 1tf:2tf ratio over time.