Resonance Reactive Ion Beam Etching Research Articles

Reactive Ion Beam Etching of GaN and AlGaN/GaN for Nanostructure Fabrication Using Methane-Based Gas Mixtures

The basic etching characteristics of electron cyclotron resonance reactive ion beam etching (ECR-RIBE) of GaN and AlGaN/GaN using methane-based mixtures have been studied in view of application to nanostructure fabrication. GaN could be etched by using a gas mixture of CH4/H2/Ar at a rate of about 10 nm/min, which is suitable for nanostructure fabrication. The etching process was also applicable to the standard AlGaN/GaN heterostructure. Etching along <1100> and <2110> stripe patterns revealed {0111} and {1121} sidewall facets, respectively, indicating that the etching is a facet-revealing process, being dominated by chemical reactions with low physical damage. However, the etching depth showed anomalous saturation at 400–500 nm, and the roughness of the surface increased with time. An in situ X-ray photoelectron spectroscopy (XPS) study detected the formation of Ga droplets. By adding N2 into the gas mixture, Ga droplet formation was suppressed, etch depth saturation disappeared and a smooth etched surface was obtained. Using the optimized etching conditions with N2 addition, an AlGaN/GaN nanowire structure with a wire width of 110 nm has been successfully fabricated.

Optimization of Electron Cyclotron Resonance Reactive Ion Beam Etching Reactors for Dry Etching of GaAs with Cl2

Dry etching of GaAs in plasma reactors is an important technology for the fabrication of optoelectronic devices. Currently, process optimization is done by trial and error, which is expensive in both time and money. Optimization techniques must therefore be developed based on a fundamental understanding of the related processes, and include a macroscopic understanding of the plasma chemistry. In this work, we examined the effect of gas flow rate on the peak intensity of the optical emission spectra of the chemical species in an etching chamber and on the etch rate of the GaAs substrate. From our results we developed a simplified model of the dry etching process of GaAs with in electron cyclotron resonance reactive ion beam etching that accounts for the degree of gas homogeneity in the reactor, especially the concentration. The effect of the reactor geometry and operating conditions on the performance of the dry etching process is well explained with this model, which can be used to optimize dry etching processes.

Improvement of Coupling Efficiency for Passive Alignment of Stacked Multifiber Tapes to a Vertical-Cavity Surface-Emitting Laser Array

High-efficiency coupling of stacked multifiber tapes to a vertical-cavity surface-emitting laser (VCSEL) array is demonstrated. Three fiber tapes, each of which includes four multimode fibers, are coupled to a 4 ×3 VCSEL array simply by inserting fibers into guiding holes fabricated on the back side of the substrate. Mirrorlike smooth floors of the holes are formed by electron cyclotron resonance reactive ion beam etching, which results in great improvement of coupling efficiency. The average measured coupling efficiency is 81.3%.

High-Power 650-nm-Band AlGaInP Visible Laser Diodes Fabricated by Reactive Ion Beam Etching Using Cl 2/N 2 Mixture

High-power 650-nm-band AlGaInP visible laser diodes having stable fundamental-transverse-mode at high temperatures were produced using electron cyclotron resonance reactive ion beam etching (ECR-RIBE). Epilayers were etched using a Cl2/N2 mixture gas, resulting in very smooth surfaces and symmetric laser mesas. Lasers that are 700-µm-long and 6%/80% coated were fabricated. The typical threshold current of these devices was as low as 46 mA at room temperature, and a stable fundamental-mode operation over 30 mW is obtained up to 70°C. The lasers operated for over 1000 h at 60°C under an output power of 25 mW, and their degradation rate was as low as lasers fabricated by the ordinary wet etching process.

Vertical etching of thick SiO2 using C2F6-based reactive ion beam etching

Anisotropic etching of deep SiO2 has been obtained using electron cyclotron resonance–reactive ion beam etching with C2F6 gas. The influence of total gas pressure and gas flow rate on the profile control and the roughness due to the etching have been determined. The sidewall angle of etched profile can be tailored by adjusting the processing conditions, and it is found that a sidewall angle of 90° for an etching of deepness around 18 μm is obtained at a pressure of 1.0 mTorr and a gas flow rate of 35 sccm. Low roughness has also been achieved for a pressure of 1.0 mTorr with the gas flow rate ranging from 25 to 40 sccm. Here, the scanning electron microscope and the scanning tunneling microscope have been used to study the etched profile and the roughness, respectively.

Investigation of boundary scattering in dry etched quantum wires by artificial manipulation of the wire boundaries

Abstract An optimized fabrication technology for quantum wires with less side wall scattering needs the understanding how to minimize the scattering mechanisms. We have used magneto transport measurements as a sensor to observe the influence of the dry etching process and the etch mask definition process on the quality of the wire boundaries. The effect of surface roughness, the distribution and density of etch induced scattering centers due to the wire definition process was investigated by an artificial manipulation of the wire boundaries. Side wall damage can be minimized using a low damage electron cyclotron resonance reactive ion beam etching process and a minimal electron beam scanning step for the etch mask exposure.

Field-induced refractive index variation spectrum in a GaInAs/InP quantum wire structure

We report the electric field induced refractive index variation spectrum in a GaInAs/InP multilayered (three layers) quantum wire structure (λg∼1.48 μm) in the range 1.484–1.65 μm with the maximum positive index variation of 4% at around 1.52 μm at an applied reverse bias voltage of 3 V. We have also observed the anisotropic property of the index variation with respect to the quantum wire direction to the input light. These multilayered quantum wire structures were fabricated by low-pressure electron cyclotron resonance reactive ion beam etching and low-pressure organometallic vapor phase epitaxy methods.

Experimental study of electron cyclotron resonance reactive ion beam etching of W and Mo thin film

A microwave electron cyclotron resonance ion source has been developed and studied for use in a reactive ion-beam system. The system has been tested and fully characterized for thin film etching. The CF4 reactive ion beam etching of W and Mo, have been investigated as a microfabrication technique for integrated semiconductor devices of submicron geometry. The etching rate has been characterized as a function of ion energy, ion-beam current density, and angle of beam incidence. It has been found that the etching rate increase linearly with current density and pressure. The rate also increases with ion energy, but the rate of increase drops as the ion energy increases. The maximum etching occurs at a beam angle of 35°.