Disclosed are approaches for forming semiconductor device cavities. One method may include providing a set of semiconductor structures defining an opening, wherein the opening has a first opening width along an upper portion of the opening and a second opening width along a lower portion of the opening, the first opening width being greater than the second opening width. The method may further include forming a blocking layer along the set of semiconductor structures by delivering a material at a non-zero angle of inclination relative to a normal extending perpendicular from a top surface of the set of semiconductor structures. The blocking layer may be formed along the upper portion of the opening without being formed along the lower portion of the opening, and wherein an opening through the blocking layer is present above the opening.

Methods for evaluating synergy of modification and removal operations for a wide variety of materials to determine process conditions for self-limiting etching by atomic layer etching are provided herein. Methods include determining the surface binding energy of the material, selecting a modification gas for the material where process conditions for modifying a surface of the material generate energy less than the modification energy and greater than the desorption energy, selecting a removal gas where process conditions for removing the modified surface generate energy greater than the desorption energy to remove the modified surface but less than the surface binding energy of the material to prevent sputtering, and calculating synergy to maximize the process window for atomic layer etching.

A method of fabricating a high electron mobility transistor is disclosed. The method comprises using an ion implantation process to amorphize a portion of the barrier layer to a specific depth. The etch rate of this amorphized portion is much faster than that of the rest of the barrier layer. In this way, the depth of the recessed regions into which the source and drain contacts are disposed is more tightly controlled. Further, the etching process may be a wet or dry etch process. The roughness of the recessed region may also be improved using this approach.

An etching method is performed in a state where a substrate is placed on a substrate support provided in a chamber of a plasma processing apparatus. In the etching method, radio-frequency power is supplied to generate plasma from a gas in the chamber. Subsequently, a negative DC voltage is applied to a lower electrode of the substrate support during the supplying of the radio-frequency power to etch the substrate with positive ions from plasma. Subsequently, the applying of the negative DC voltage to the lower electrode and the supplying of the radio-frequency power are stopped to generate negative ions. Subsequently, a positive DC voltage is applied to the lower electrode in a state where the supply of the radio-frequency power is stopped to supply the negative ions to the substrate.

A method of fabricating a semiconductor structure includes forming a GaN-based semiconductor layer on a substrate, forming a silicon-containing insulating layer on the GaN-based semiconductor layer, forming a recess in the silicon-containing insulating layer in a first etching step, wherein the first etching step is performed by using a fluorine-containing etchant and applying a first bias power, and enlarging the recess to extend into the GaN-based semiconductor layer in a second etching step, wherein the second etching step is performed by using the same fluorine-containing etchant as the first etching step and applying a second bias power that is greater than the first bias power. In addition, a method of fabricating a high electron mobility transistor is provided.

A method for controlling an electrostatic attractor, which attracts an electrode to a gas plate provided in an upper portion of a plasma processing apparatus, includes, among a plasma generation period in which plasma is generated by the plasma processing apparatus and an idle period in which no plasma is generated by the plasma processing apparatus, applying voltages having polarities different from each other to first and second electrodes of the electrostatic attractor in at least the idle period.

Fabricating a vertical-channel junction field-effect transistor includes forming an unintentionally doped GaN layer on a bulk GaN layer by metalorganic chemical vapor deposition, forming a Cr/SiO.sub.2 hard mask on the unintentionally doped GaN layer, patterning a fin by electron beam lithography, defining the Cr and SiO.sub.2 hard masks by reactive ion etching, improving a regrowth surface with inductively coupled plasma etching, removing hard mask residuals, regrowing a p-GaN layer, selectively etching the p-GaN layer, forming gate electrodes by electron beam evaporation, and forming source and drain electrodes by electron beam evaporation. The resulting vertical-channel junction field-effect transistor includes a doped GaN layer, an unintentionally doped GaN layer on the doped GaN layer, and a p-GaN regrowth layer on the unintentionally doped GaN layer. Portions of the p-GaN regrowth layer are separated by a vertical channel of the unintentionally doped GaN layer.

A method comprises providing a substrate comprising an n-type Al/In/GaN semiconductor material. A surface of the substrate is dry-etched to form a trench therein and cause dry-etch damage to remain on the surface. The surface of the substrate is immersed in an electrolyte solution and illuminated with above bandgap light having a wavelength that generates electron-hole pairs in the n-type Al/In/GaN semiconductor material, thereby photoelectrochemically etching the surface to remove at least a portion of the dry-etch damage.

A process of preparing a wafer having a diameter of two inches or more, at least a surface of the wafer being formed from a group III nitride crystal, including preparing an alkaline or acidic etching liquid containing a peroxodisulfate ion as an oxidizing agent that accepts an electron, accommodating the wafer such that the surface of the wafer is immersed in the etching liquid such that the surface of the wafer is parallel with a surface of the etching liquid; and radiating light from the surface side of the etching liquid onto the surface of the wafer without agitating the etching liquid. First and second etching areas disposed at an interval from each other are defined on the surface of the wafer. In the process of radiating the light onto the surface of the wafer, the light is radiated perpendicularly onto surfaces of the first and second etching areas.

A light emitting diode device includes a thin film transistor substrate having a plurality of light emitting areas, a first diode electrode and a second diode electrode on the thin film transistor substrate, a first passivation pattern between the first diode electrode and the second diode electrode, a plurality of micro light emitting diodes on the first passivation pattern, a first bridge pattern on the micro light emitting diodes and electrically connecting the first diode electrode to the micro light emitting diodes, and a second bridge pattern on the first bridge pattern and electrically connecting the second diode electrode to the micro light emitting diodes, wherein each sidewall of each of the micro light emitting diodes and each sidewall of the first passivation pattern form a same plane.