An extensive investigation has been performed on inductively coupled plasma etching of InP. An important motivation for this work is the fabrication of high-aspect-ratio holes for photonic crystals. The essential chemistry is based on Cl 2 with the addition of N 2 or O 2 for sidewall passivation. The influence of different process parameters such as gas flows, temperature, pressure, ion energy, and inductively coupled plasma power on the hole geometry is presented. It is concluded that photonic crystals can be etched with Cl 2 only; however, temperature and pressure control is critical. Adding passivation gases largely broadens the window in the parameter space for hole etching. Most importantly, etching of narrow holes can be carried out at higher temperatures where the etching is mass limited and spontaneous etching of InP by Cl 2 occurs.

Articles you may be interested inImproving soft magnetic properties of nanometer CoNbZr films in gigahertz frequency range by electrical pulse annealing J. Appl. Phys. 113, 17A341 (2013); 10.1063/1.4800744Microfluxgate sensor with amorphous cobalt (Co-Nb-Zr) soft magnetic core for electronic compass Dry etch behavior of CoNbZr in an inductively coupled plasma of Cl 2 /BCl 3 at elevated temperatures has been studied. Etch behavior of the alloy is ion induced with a strong chemical enhancement. The etch rate shows nonstoichiometric behavior when compared with the constituting elements. The increase by about 35% is attributed to interactive effects. A further enhancement up to about 40% is obtained under simultaneous exposure of deep ultraviolet irradiation. A fast anisotropic dry patterning process for CoNbZr has been developed, with etch rates up to 300 nm/min at 220°C.

Articles you may be interested inA high-speed magnetic tweezer beyond 10,000 frames per second Rev. Sci. Instrum. 84, 044301 (2013); 10.1063/1.4802678 High-force NdFeB-based magnetic tweezers device optimized for microrheology experiments Rev. Sci. Instrum. 83, 053905 (2012);Dry etch behavior of Fe in inductively coupled chlorine-based plasma at elevated temperatures has been investigated. Etch rates up to 300 nm/min at 190°C were achieved, with good selectivity towards SiO 2 and Al 2 O 3 masks. Etching did not take place in pure Cl 2 plasma or Ar/Cl 2 plasma, but required the addition of a few percent BCl 3 or SiCl 4 . The process was found to be a combination of spontaneous and ion enhanced chemical etching. Simultaneous exposure to ultraviolet light from an external source did not enhance the etch rate, but did shorten the inhibition time of the etching.

Faceting of the etch masks and chlorinated etch residues can reduce the magnetization of patterning magnetic materials substantially, and therefore, constitutes a considerable concern. To get more insight into the magnetization losses, CoFeB dots were etched in a high ion density Cl2-based plasma with a width ranging from 0.3to6.4μm. The magnetic properties of the CoFeB dots were measured by magnetometry. Submicrometer CoFeB dots showed significant magnetization reductions despite H2O rinsing. Scanning electron microscopy (SEM) studies revealed that etching in a Cl2-based plasma caused faceting of the masks, leading to sloped sidewalls. SEM pictures were used to determine the geometric volume, which was compared to the effective magnetic volume resulting from the magnetometry measurements. The SEM data are in good agreement with the magnetometry data, and a chloride penetration depth of only a few nanometers could be derived, indicating that the postetch rinsing is sufficient to prevent considerable corrosion of the CoFeB dots.