Selective Silicon Epitaxy Using Atomic Hydrogen Nodule Removal
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Solution Overview
Problem
Existing epitaxial deposition methods struggle to remove residual or non-selective growth (nodular defects) from undesired locations without damaging the epitaxial layers.
Innovation Solution
The use of atomic hydrogen radicals to etch substrates and remove nodular defects, combined with thermal annealing of the epitaxial layers at temperatures of 600 degrees Celsius or higher.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used to remove nodular defects, then nodules are removed from undesired locations, but epitaxial layers are damaged or interfered with
Solution Approach 1:
The patent applies local quality by making the etching process selective to specific crystal orientations. The silicon substrate has different crystal planes (e.g., <100> vs <111>) that etch at different rates when exposed to the same etchant. By controlling the substrate orientation and etching conditions, nodules on undesired locations are removed while the epitaxial layers on desired locations remain intact due to their different crystal orientation resistance to etching
Solution Approach 2:
The patent utilizes parameter changes by adjusting etching parameters such as etchant composition, temperature, and exposure time to achieve selective removal. By optimizing these parameters, the etching process becomes highly selective for nodular defects while sparing the epitaxial layers, resolving the contradiction between defect removal and layer protection
2Manufacturing precision
If selective epitaxial growth is performed, then epitaxial layers are grown on desired locations, but residual or non-selective growth occurs in undesired locations causing defects
Solution Approach 1:
The patent applies local quality through selective epitaxial growth where the substrate surface has different crystal orientations in different regions. The epitaxial growth occurs selectively on regions with favorable crystal orientations (e.g., <100> planes) while regions with other orientations (e.g., <111> planes) resist growth. This creates spatially varying growth properties that enable precise control over where epitaxial layers form, eliminating non-selective growth in undesired locations
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 effectively removes nodular defects from undesired locations while minimizing the risk of damage to the epitaxial layers, thereby improving the quality and integrity of the deposited layers.
Implementation Method 1
The etching includes exposing the substrate to atomic hydrogen radicals
Implementation Method 2
thermally annealing the epitaxial layer to an anneal temperature that is 600 degrees Celsius or higher
Implementation Method 3
selectively growing an epitaxial layer on one or more crystalline surfaces of a substrate
Data Source
AI summary
Aspects of the present disclosure relate to apparatus, systems, and methods of using atomic hydrogen radicals with epitaxial deposition. In one aspect, nodular defects (e.g., nodules) are removed from epitaxial layers of substrate. In one implementation, a method of processing substrates includes selectively growing an epitaxial layer on one or more crystalline surfaces of a substrate. The epitaxial layer includes silicon. The method also includes etching the substrate to remove a plurality of nodules from one or more non-crystalline surfaces of the substrate. The etching includes exposing the substrate to atomic hydrogen radicals. The method also includes thermally annealing the epitaxial layer to an anneal temperature that is 600 degrees Celsius or higher.