Structures and methods for forming highly uniform and high-porosity gallium-nitride layers with sub-100-nm pore sizes are described. Electrochemical etching of heavily-doped gallium nitride at low bias voltages in concentrated nitric acid is used to form the porous gallium nitride. The porous layers may be used in reflective structures for integrated optical devices such as VCSELs and LEDs.

A method for producing at least one pattern in a substrate is provided, including providing a substrate having a front face surmounted by at least one masking layer carrying at least one mask pattern, carrying out an ion implantation of the substrate so as to form at least one first zone having a resistivity ρ1 less than a resistivity ρ2 of at least one second non-modified zone, after the ion implantation step, immersing the substrate in an electrolyte, and removing the at least one first zone selectively at the at least one second zone, the removing including at least an application of an electrochemistry step to the substrate to cause a porosification of the at least one first zone selectively at the at least one second zone.

A method for producing at least one pattern in a substrate is provided, including providing a substrate having a front face surmounted by at least one masking layer carrying at least one mask pattern, carrying out an ion implantation of the substrate so as to form at least one first zone having a resistivity ρ1 less than a resistivity ρ2 of at least one second non-modified zone, after the ion implantation step, immersing the substrate in an electrolyte, and removing the at least one first zone selectively at the at least one second zone, the removing including at least an application of an electrochemistry step to the substrate to cause a porosification of the at least one first zone selectively at the at least one second zone.

A method includes dispensing a chemical solution including charged ions onto a semiconductor substrate to chemically etch a target structure on the semiconductor substrate, and applying an electric field on the semiconductor substrate during dispensing the chemical solution on the semiconductor substrate, such that the charged ions in the chemical solution are moved in response to the electric field.

A method includes dispensing a chemical solution including charged ions onto a semiconductor substrate to chemically etch a target structure on the semiconductor substrate, and applying an electric field on the semiconductor substrate during dispensing the chemical solution on the semiconductor substrate, such that the charged ions in the chemical solution are moved in response to the electric field.

The present disclosure provides a semiconductor structure etching solution, including an etchant, an ionic strength enhancer having an ionic strength greater than 10.sup.−3 M in the semiconductor structure etching solution, and a solvent having a dielectric constant lower than a dielectric constant of water.

The present disclosure provides a semiconductor structure etching solution, including an etchant, an ionic strength enhancer having an ionic strength greater than 10.sup.−3 M in the semiconductor structure etching solution, and a solvent having a dielectric constant lower than a dielectric constant of water.

Various technologies are described herein pertaining to electrochemical etching of a semiconductor controlled by way of a laser that emits light with an energy below a bandgap energy of the semiconductor.

Embodiments of the present disclosure generally relate to methods of forming optical devices comprising nanostructures disposed on transparent substrates. A substrate, such as a silicon wafer, is provided as a base for forming an optical device. A transparent layer is disposed on a first surface of the substrate, and a structure layer is disposed on the transparent surface. An etch mask layer is disposed on a second surface of the substrate opposite the first surface, and a window or opening is formed in the etch mask layer to expose a portion of the second surface of the substrate. A plurality of nanostructures is then formed in the structure layer, and a portion of the substrate extending from the window to the transparent layer is removed. A portion of the transparent layer having nanostructures disposed thereon is then detached from the substrate to form an optical device.

Embodiments of the present disclosure generally relate to methods of forming optical devices comprising nanostructures disposed on transparent substrates. A substrate, such as a silicon wafer, is provided as a base for forming an optical device. A transparent layer is disposed on a first surface of the substrate, and a structure layer is disposed on the transparent surface. An etch mask layer is disposed on a second surface of the substrate opposite the first surface, and a window or opening is formed in the etch mask layer to expose a portion of the second surface of the substrate. A plurality of nanostructures is then formed in the structure layer, and a portion of the substrate extending from the window to the transparent layer is removed. A portion of the transparent layer having nanostructures disposed thereon is then detached from the substrate to form an optical device.