As modern technology continues to become smaller and more powerful, the semiconductors within such technologies must also adapt. Historically, two-dimensional (2D) devices have dominated applications because of their relative ease of fabrication and epitaxial growth. Increasingly, three-dimensional (3D) structuring at the nanoscale is becoming important for emerging applications. As the device size is reduced, quantum functional properties, not available at larger scales, can be realized in low dimensional structures such as nanodots (NDs) and nanowires (NWs).
During the manufacture of these devices, the epitaxial growth of the layer structures is the most fundamental when there is a non-negligible lattice mismatch between a substrate and the device layers grown on it. One of the ways to overcome this is to employ nanoscale patterned growth (NPG); simply the localization of epitaxy on a planar substrate by a mask film that provides an epitaxial boundary. As device size is reduced further, 2D structures will no longer be able viable and will need to be evaluated as a 3D event. Depending on the 3D design of the mask films, the geometric shape evolution is guided by the suppression or encouragement of certain facets allowed in its equilibrium crystal shape (ECS). The NPG relying on ECS is highly dependent on the substrate orientation and the pattern shape implemented on it, which sets the conditions of the initial faceting of an epilayer and its associated shape evolution. This invention, referred to as pattern-guided epitaxy (PGE), focuses on this point and presents several methods for the demonstration of 3D nanostructures based on ECS initiated from a patterned substrate.
Researchers at the University of New Mexico have discovered a way to achieve desired shaping during epitaxial growth. The shape of a device can be fully or partially projected into a mask film as a pattern by etching so that the epitaxy can be guided to the growth directions and dimensions predetermined by the pattern. This invention uses the facets generated during pattern-guided epitaxy (PGE) which allows for growth directions not obtainable on the original substrate. This is necessary for the shaping of the desired device and permits additional freedom in the selection of substrate orientation and the 3D mask pattern.
- Allows for specific growth shaping
- Substrate orientation freedom
- Unlimited mask patterns
- Offers unique growth directions
- Enables 3D nanostructure demonstrations
- Design/control geometric shape of nanostructures with mask profile
- Consumer goods such as electronics
- Semiconductor research
- Optoelectronic devices
- Quantum functional devices
- Large lattice-mismatched heteroepitaxy
Name: Andrew Roerick