Making nanochannels and nanotunnels
Inventors
Assignees
United States Department of Commerce
Publication Number
US-9809452-B2
Publication Date
2017-11-07
Expiration Date
2037-02-27
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Abstract
A process for making a nanoduct includes: disposing an etchant catalyst on a semiconductor substrate including a single crystal structure; heating the semiconductor substrate to an etching temperature; introducing an oxidant; contacting the semiconductor substrate with the oxidant in a presence of the etchant catalyst; anisotropically etching the semiconductor substrate by the etchant catalyst in a presence of the oxidant in an etch direction that is coincident along a crystallographic axis of the semiconductor substrate; and forming the nanoduct as the etchant catalyst propagates along a surface of the semiconductor substrate during anisotropically etching the semiconductor substrate, the nanoduct being crystallographically aligned with the crystallographic axis of the semiconductor substrate.
Core Innovation
The invention provides a process for making a nanoduct by disposing an etchant catalyst on a semiconductor substrate comprising a single crystal structure, heating the substrate to an etching temperature, introducing an oxidant, and contacting the substrate with the oxidant in the presence of the etchant catalyst. This process anisotropically etches the semiconductor substrate in an etch direction coincident along a crystallographic axis of the substrate, forming a nanoduct as the catalyst propagates along the substrate surface, which is crystallographically aligned with the substrate's crystallographic axis.
The nanoduct formed can be a nanochannel, nanotunnel, or combinations thereof, including nanofrustocones and truncated nanofrustocones that may be convergent or divergent. The anisotropic etching by the etchant catalyst is site specific and enables control over the direction and dimensions of the nanoduct. The process supports formation on semiconductor substrates comprising elements or compounds from groups 11, 12, 13, 14, 15, and 16 of the periodic table, including silicon, gallium arsenide, indium phosphide, and others, with the oxidant selected to convert the substrate into volatile oxides that escape during etching.
Claims Coverage
The patent includes one independent claim describing a process for making a nanoduct with multiple inventive features.
Process for making a nanoduct using an etchant catalyst and oxidant
Disposing an etchant catalyst on a single crystal semiconductor substrate; heating to etching temperature; introducing an oxidant; contacting the substrate with oxidant in presence of the catalyst; anisotropically etching the substrate by the catalyst in an etch direction coincident along a crystallographic axis; and forming a nanoduct as the catalyst propagates along the substrate surface, with the nanoduct crystallographically aligned with the crystallographic axis.
The claims elaborate on the process steps including patterning the catalyst, droplet formation, dissolution and oxidation of substrate portion to volatile oxides, etching covered portions forming nanotunnels, blocking layers to terminate etching, and specify suitable etchant catalysts, substrates, and nanoduct structures, thereby covering a detailed method for controlled anisotropic etching to form crystallographically aligned nanoducts.
Stated Advantages
The etchant catalyst alloys with semiconductor atoms and locally catalyzes oxidation allowing anisotropic, site-specific etching along a crystallographic direction.
Control over direction and dimensions of nanochannels enables scalable surface nanoengineering.
Nanochannels or nanotunnels formed can be used in advanced materials, multifunctional heterogeneous nanosystems, electro-optical devices, and nanofluidic articles.
Nanoducts can act as filters, separators, or concentrators based on molecular size, shape, and weight.
Documented Applications
Development of advanced materials.
Multifunctional heterogeneous nanosystems including electro-optical devices.
Nanofluidic articles and platforms.
Cutting apart regions of thin films and templates for nanostructure growth.
Control and integration in nanoscale devices and nanomaterial processing.
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