Reactive Ion Etching Experiments Research Articles

Influence of the side etching effect in DRIE on performance of electrostatic linear comb-drive actuators

Side etching and scalloping are unwanted but unavoidable phenomenon occurring during fabrication process of micro electro-mechanical system devices with the deep reactive ion etching technology. This paper reports the influence of deep reactive ion etching fabrication errors on the geometrical dimension (as a comb finger shape, width of the suspension beam), electrostatic force and displacement of electrostatic linear comb-drive actuators. A number of deep reactive ion etching experiments were carried out in order to find out the optimal etching and passivation time, which allows to achieve vertical and smooth sidewall, as well as acceptable side etching value. Discussion and evaluation of deviation between the theoretically calculated and measured displacements of the electrostatic linear comb-drive actuator were also reported.

The Role of Si during the Growth of GaN Micro- and Nanorods

The role of Si during the metal–organic vapor phase epitaxy of GaN rods is investigated. Already a small amount of Si strongly enhances the vertical growth of GaN. Reactive ion etching experiments show that the inner volume of the rod is much more strongly etched than the m-plane surface layer. Transmission electron microscopy and energy dispersive X-ray spectroscopy measurements reveal that Si is predominiantly incorporated in the surface layer of the m-plane sidewall facets of the rods. The formation of a SiN layer prevents growth on and etching of the m-planes and enhances the mobility of atoms promoting vertical growth. Annealing experiments demonstrate the extraordinary thermal resistivity in comparison to undoped GaN rod structures and GaN layers. The subsequent InGaN quantum well growth on the GaN rods reveals the antisurfactant effect of the SiN layer. A model based on the vapor–liquid–solid growth mode is proposed. The results help to understand the role of Si during growth of GaN rod structures to improve the performance of rod based light emitting and electronic devices.

Anodic 3D nanostructuring for tailored applications

Electrochemistry can be used to fabricate different three dimensional objects on the nanometre scale. Porous anodic aluminium oxide (AAO) membranes with varying but controlled morphologies are used in several complementary experiments in physics and biology. The present paper gives a description of the membrane fabrication procedure and presents a selection of applications based on the use of the membranes as evaporation masks in crystal growth experiments, as masks in reactive ion etching experiments or as moulds to fabricate arrays of ordered polymer nanopillars. Applications in energy storage are also briefly mentioned. Finally the fabrication of TiO2 nanotubes (TNT) is described. Their anodic formation is very close to that of the AAO membranes and TNTs offer additional perspectives for applications.

Novel anodic aluminum oxide‐based nanofabrication: applications in physics and biology

AbstractPorous anodic aluminum oxide (AAO) membranes with varying but controlled morphology are used in several complementary experiments in physics and biology. The present paper gives a description of the membrane fabrication procedure and presents a selection of applications based on the use of the membranes when used as evaporation masks in growth experiments, as masks in reactive ion etching experiments or as molds to fabricate arrays of ordered polymer nanopillars. Copyright © 2010 John Wiley & Sons, Ltd.

Utilisation of JSR and BCB resists for the construction of gray scale microstructures

This paper reports on the use of two well-known photoresists, the JSR and BCB for the construction of gray scale structures which have a wide range of applications in the semiconductor/electronics industry. Reactive ion etching experiments were carried out in order to define the etching rate of the resist JSR and cyclotene using a combination of two different gases. Argon and Oxygen were used separately in order to determine the etching rate of the photoresist and the cyclotene by changing the following parameters: concentration, gas pressure and power of the RF unit. New reactive ion etching experiments were performed using combinations of the two gases in order to establish the optimum ratio of the two gases for accomplishing the desirable gray scale structures.

Angular dependence of SiO2 etching in a fluorocarbon plasma

SiO 2 etch rates in a CF4 plasma were obtained at various surface angles using a Faraday cage with pinholes on the upper plane through which ions are incident on the substrate fixed at various angles inside the cage. The reactive ion etching experiments were performed at 5 mTorr in a wide bias-voltage range from −100 to −800 V. The normalized etch-yield curves showed virtually the same angular dependence regardless of the ion incident energy. The curve shape was similar to that of physical sputtering except that the ratio of the maximum yield to that at 0° was as low as about 1.3. This is the deviation from the cosine dependence characteristic of chemical sputtering, which is the main mechanism of SiO2 etching in a fluorocarbon plasma. This deviation is partly attributed to the fluorocarbon polymer film, which existed as a few monolayers-thick film on the substrate surface at low angles near 0° but as a submonolayer at high angles between 45° and 75°. The effect of the film-coverage difference on the deviation is explained in terms of reactant chemisorption, product desorption, energy deposited by ions causing the collision cascade, and incorporation of projectiles and recoils leading to the mixing effect. The deviation is also attributed to physical sputtering, which became comparable to chemical sputtering as the ion energy increased. Both factors, i.e., the formation of the thin fluorocarbon polymer film and physical sputtering, are supposed to contribute to the curve deviation, although their relative importance changed with the ion incident energy.

Reactive ion etching for submicron structures of refractory metal silicides and polycides

Refractory metal silicides and n+ polysilicon/silicides are of particular interest for VLSI gate and interconnection technology. Reactive ion etching experiments have been conducted on sputter-deposited films of MoSi2, CVD n+ polysilicon, and thermal SiO2 using admixtures of SF6 with O2. The influence of partial pressure and total pressure on profile control and etch selectivity has been determined. Highly anisotropic etching of n+ polysilicon and MoSi2 was obtained using a gas mixture of SF6 plus 50% oxygen. Examples of 0.2μ anisotropically etched structures of silicides and n+ polysilicon/silicide stacked films have been realized using electron beam lithography and one step dry etching. Mechanisms of profile control involved in the SF6/O2 system are discussed. In addition, exploratory reactive ion etching studies using SiF4/Cl2 gas mixtures for these materials and TaSi2 have been carried out.