Dry Etching of Sol-Gel Pzt

(alpha) -C:H films were applied to fabricate photonic band gap (PBG) structures in the silicon substrate by SF<SUB>6</SUB>N<SUB>2</SUB>-based reactive ion etching (RIE). The influence of RIE parameters on (alpha) C:H films structure and etching rate was investigated int his study. It is shown that RIE rate for (alpha) -C:H films changes from 26 nm/min to 38 nm/min with the integrated intensity ratios I<SUB>D</SUB>/I<SUB>G</SUB> varied from 0.65 to 1.1. It is evident that increase in etching rate is determined by increasing quantity of sp<SUP>2</SUP> bonding in the synthesized (alpha) -C:H films. RIE does not change structure of the (alpha) -C:H masking films. However, non- uniform character of RIE takes place due to the non- homogeneous graphite clusters in (alpha) -C:H masking films. However, non-uniform character of RIE takes place due to the non-homogeneous graphite clusters in (alpha) -C:H masking films. By changing parameters of silicon etching, such as RF power density, pressure and negative bias voltage, anisotropy was varied in wide range and microstructures of different shape were obtained.

Lead zirconate titanate thin films have been deposited by reactive sputtering using an independently RF-supplied three-target (Pb, Zr, Ti) system at a substrate temperature of 615[ddot]C. The lead content depended greatly on the input rf power at the Ti target, the highest power among the three targets, indicating resputtering. Remanent polarization (Pr) was 26.6 μC/cm2 for a PZT film of 3200 Å thickness. Dependence of etching rate of PZT and Pt on incidence angle of the Ar ion beam in ion milling was investigated to optimize selectivity.

Reactive ion etching of diamond as a means of enhancing chemically-assisted mechanical polishing efficiency

Silicon (Si) etching process with low temperature is used for initial processing of semiconductor field emitter array cathodes for vacuum microelectronics, for optical reflecting gratings, for opto- and micromechanical devices. Most of them are performed by dry etching process especially in reactive ion etching (RIE) method with fluorocarbon-gases such as CF4, CHF3 and C3F8. In this work, results are shown that reactive ion etching of silicon using CF4/H2 is capable at meeting the requirement (anisotropy, high etch rate and high selectivity, simultaneously) similar to that by using reactive ion etching with fluorine-containing plasma. We have investigated the etching rate dependency on the percentage of hydrogen in the gas mixture, the total pressure and flow gas and found that by using a gas mixture with 33% of H2, the optimum rate of Si is achieved. The etch rate are found to increase with voltage, attaining a maximum rate 1780 Å/min at -482V. Surface morphology of the etched samples is characterized by scanning electron microscopy and atomic force microscopy. The results revealed that the etched surface was anisotropic and the smoothness of the etched surface is comparable to that of polished wafer.

The lead zirconate titanate (PZT) thin films were fabricated using sol-gel spin coating onto Pt/Ti/glass substrates. Effects of the holding time for pyrolysis and the coating cycle on the preferred orientation of the PZT thin films were studied. The films were fabricated with different coating cycles (3, 5, 7, 9, 11), dried at 330 °C for different holding times (5, 30, 60 min), and then annealed at the same temperature of 650 °C using rapid thermal annealing (RTA). The preferred orientations of the films were investigated using x-ray diffraction and glancing angle x-ray diffraction. The microstructure and the selected area diffraction pattern of the PZT thin films were also investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively.

Optimum sample preparation is essential to obtain reliable data in microstructure analysis. Whereas traditional metallographic preparation techniques, using mechanical polishing and chemical etching, are sufficient for many applications, these methods can be unsatisfactory for high-technology materials, complex assemblies, and smaller components. Broad-beam argon ion milling (AIM), using high-energy ion bombardment to remove material or modify the surface of a specimen, can provide a substantial improvement in specimen quality for many difficult materials and components. Directing energetic argon ions toward the specimen at a low angle of incidence gradually removes material at the atomic level to produce flat surfaces with no deformation or other disturbance of the material microstructure. Especially for multi-phase materials with low hardness or soft constituents, polishing by ion milling at low-angles results in optimum surfaces for light microscopy, scanning electron microscopy (SEM), or electron backscattered diffraction (EBSD). Surface modification to produce contrast between phases or reveal other microstructural features can be realized with higher milling angles. This provides a great advantage for components consisting of noble metals, like gold and platinum, or corrosion-resistant alloys bonded to less noble metals, which are frequently difficult or impossible to prepare with chemical etching. Microstructure contrast with ion milling is also useful for extremely fine structures, such as ultra-fine grains, that can be obscured by chemical etching.

In the microwave induced plasma deposition of diamond from methane-hydrogen-oxygen mixtures, the variables available for controlling the microstructure of the resulting films are the plasma composition and density, the substrate surface properties, and the temperature. It has been demonstrated that the competition between nucleation site formation and the rate of reactive plasma etching is the critical feature in the development of the film microstructure on silicon substrates. On diamond substrates, the favorable lattice match dominates and homo-epitaxial films are formed over a wide temperature range. Raman scattering studies also demonstrate that the reactive etching of the diamond surface by oxygen-containing species is critical to the removal of non-diamond carbon species over the temperature range 450–1050 °C.

Evaluation of fluorinated polyimide etching processes for optical waveguide fabrication

Chlorine-based reactive ion etching (RIE) of a high-permeability Co–Zr–Nb film has been carried out. The etching rate was only about 10 nm/min in pure Cl2 in the temperature range in which anisotropic ion etching was dominant. Addition of BCl3 to the Cl2 resulted in an increase in the etching rate at low temperature. The activation energy in BCl3–Cl2 RIE was about 0.5 eV, whereas that in pure Cl2 RIE was 1.0 eV. The optimum BCl3 content was around 30 vol.%. The etching rate reached 750 nm/min at 1.2 W/cm2 RF power density and 300° C etching temperature. This improvement is due to the heavier mass and the higher ionization rate of BCl3 than those of Cl2. The ratio of the side etching rate to the depth-etching rate was about 30%, when the RF power density was 1.2 W/cm2 in BCl3–Cl2 RIE. The side etching was suppressed by both an increase in the RF power and addition of SiCl4 or SiCl4–O2 to the BCl3–Cl2. Anisotropy was promoted by both an increase in the ion energy and sidewall protection by Si or Si-oxide. An etching rate of 200 nm/min at 150° C and 2 W/cm2 RF power density in BCl3–Cl2–SiCl4 RIE has been achieved. The etching selectivity vs SiO2 was 20 and the side-etching rate was only 2% of the depth-etching rate.

A method for directly observing the ferroelectric domain structure by scanning electron microscopy after argon ion milling has been established. Its advantages are exemplified by exposing the domain structure in three widely used ferroelectric ceramics, BaTiO3, (Na,K)NbO3, and Pb(Ti,Zr)O3. Stable high‐resolution images revealing domains with widths &lt;30 nm have been obtained. The domain contrast is caused by electron channeling and is strongly dependent on the sample tilt angle. Owing to a strain‐ and defect‐free surface generated by gentle ion milling, pronounced orientation contrast is observed.

From measurements of optical emission and silicon etch rate, we are able to separate contributions due to the chemical etching and the ion-bombardment enhanced etching in the CF4+O2 reactive ion etching process. The chemical etching part of undoped polysilicon etch rates is linearly proportional to the ground state fluorine population and the ion bombardment part is proportional to the dc self-bias voltage (V2.3bi). The chemical etching predominates during plasma etching, giving rise to the isotropic etch profile, while both the chemical etching and the ion-bombardment enhanced etching mechanisms coexist during reactive ion etching. A degree of the etch anisotropy in reactive ion etching is determined by competition between the chemical etching and the ion-bombardment enhanced etching, and can be expressed by an equation which only involves two physical quantities, etch rate and fluorine concentration, experimentally measurable in plasma etching and reactive ion etching. The silicon loading effect leads to a substantial decrease in a number density of the ground state fluorine and consequently makes an etch profile more directional by reducing a contribution due to the chemical etching. Also, we have identified important process parameters which influence etch profiles.

The reactive ion etching (RIE) of commercial PMMA sheet has been examined in pure 02 and CHF3/02 plasma. The aim of this study was to optimize the etching PMMA process parameter. Addition of CHF3 , which have a surface passivation effect, to Oxygen plasmas should be obtained vertical edges at an acceptable etch rate. A RIE parallel plate reactor was used and electroplated nickel film was used as mask. We discuss the influence of pure 02 and O2/CHF3 etching gas on etching profile, the influence of the etching parameters such as gas pressure and CHF3/O2 ratio on vertical etching rate, lateral etching rate and etching profile was also investigated.

The reactive ion etching (RIE) of Si/sub 1-x/Ge/sub x/ alloy with hydrogen bromide is described. The technologies of producing Si/sub 1-x/Ge/sub x/ devices are compatible with those of producing silicon devices, which is the major reason why Si/sub 1-x/Ge/sub x/ technologies have been developed so fast in the past few years. One of the key technologies is the etching of Si/sub 1-x/Ge/sub x/ materials during the production of devices. The materials used were grown by SIVA32 MBE systems under 6.0/spl times/10/sup -10//spl sim/6.0/spl times/10/sup -11/ Torr. The experimental results showed that the etch rate of Si/sub 1-x/Ge/sub x/ RIE increased monotonically with increased Ge-content in Si/sub 1-x/Ge/sub x/. The higher Ge-content is, the higher the ratio of Si/sub 1-x/Ge/sub x/ etch rate to Si etch rate is. For instance, when x=0.1, the ratio is 1.12; but, when x=0.18, the ratio is 1.35. The RIE rate of Ge epitaxial layers is higher than that of Si/sub 1-x/Ge/sub x/, and is almost four times as high as that of monocrystalline Si.

Comparative study on dry etching of polycrystalline diamond thin films

Anisotropic etching of titanium silicide is essential if its low resistivity gate properties are to be utilized on scaled MOS devices. and plasmas, as well as ion milling, were used to etch composite titanium silicide/polysilicon films, with each displaying definite drawbacks. plasmas yielded rough etching and etch residue, presumably due to the high oxygen content of the silicide film and the relatively high selectivity (low oxide etch rate) of the etch. reactive ion etching and ion milling produced smooth etching but lacked the selectivity to stop on thin underlying gate oxides. A combination of these processes, however, provided successful anisotropic patterning of such structures. A nonselective, smooth etching reactive ion etch was used to etch through the silicide layer, followed by a higher selectivity plasma etch through the underlying polysilicon down to the thin gate oxide.