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Proceedings ArticleDOI

Low temperature reactive ion etching for bulk micromachining

S. Shimizu1, Katsutoshi Kuribayashi1, M. Ohno1, T. Taniguchi1, T. Ueda 
06 Nov 1994-pp 48-52
TL;DR: In this paper, a low temperature reactive ion etching (RIE) apparatus for the bulk micromachining was fabricated and the etching characteristics were investigated, and the high etch rate of 0.022 /spl mu/m/s and the low normalized side etch ratio was realized at the cathode temperature of -80/spl deg/C.
Abstract: To make three dimensional micron structures, the directional deep etching techniques are very important. The directional wet etching technique is often used for the bulk micromachining. However, directions of the wet deep etching and profiles of products are restricted by the crystalline orientation of silicon substrate. To solve this problem, high speed and deep directional dry etching processes have been studied. The low temperature reactive ion etching (RIE) apparatus for the bulk micromachining was fabricated and the etching characteristics were investigated. The high etch rate of 0.022 /spl mu/m/s and the low normalized side etch ratio of 0.021 were realized at the cathode temperature of -80/spl deg/C. The etch rate is equal or a little higher than that of the directional wet etching. >
Citations
More filters
Journal ArticleDOI
03 Jun 2005
TL;DR: In this article, a suspended coaxial transmission line with an air propagation medium is presented, where short-circuit stubs suspend the center conductor of the coaxial structure which is used in the design of two dual-mode narrowband microwave filters.
Abstract: A suspended coaxial transmission line with an air propagation medium is presented. The transmission line is made only of metal, thereby avoiding dielectric and radiation losses. Short-circuit stubs suspend the centre conductor of the coaxial structure which is used in the design of two dual-mode narrowband microwave filters. Stacked layers of copper sheets are used to form the square coaxial transmission line, which has low loss and low dispersion.

27 citations

Journal ArticleDOI
TL;DR: In this article, the authors used step-index fiber theory to investigate the dispersion properties of photonic-crystal fibers with small hole diameters and showed that the results obtained in this way are only limited by the degree of accuracy to which the values of have been computed.
Abstract: of the core and cladding are very similar” [6]. As observed from Figure 3, this is only true for photonic-crystal fiber with small hole diameters. The validity of this approach may therefore become questionable for larger hole diameters. More accurate results may be obtained by using numerical differentiation to investigate the dispersion properties of photoniccrystal fibers. Using values of n1 obtained by the Sellmeier equation and corresponding values of n2eff (Fig. 3), the values of propagation constant are calculated for different wavelengths using step-index fiber theory. The values of () against (k) are modeled using a piecewise polynomial interpolation of order 3. The normalized GVD in Eq. (3) is then obtained by differentiating the interpolating polynomials. This procedure includes the effect of dispersion in silica and does not need the addition of material dispersion. Since no other approximations are used, the validity of results obtained in this way is only limited by the degree of accuracy to which the values of have been computed. Figure 5 shows the calculated results using the two different approaches. The plots are given for the range of wavelength of interest in current optical-fiber communication systems. Moreover, outside this range of wavelength, the material (silica) dispersion predominates over waveguide dispersion. It may be observed that the normalized GVD calculated by both procedures agree for small hole diameter, but not for larger holes. This confirms the fact that the separation of normalized GVD into the two components, as in Eq. (4), is only valid for a limited range of hole diameters. The cause can be seen by examining the variation of the refractive index of silica and that of the effective refractive index with wavelength shown in Figure 3. For small hole diameter, the variation of effective refractive index with wavelength closely follows that of the refractive index of silica. However, for larger holes, the variation of effective index with wavelength diverts from that of the refractive index of silica, thus violating the principle upon which the separation is based [6]. CONCLUSION

18 citations

Dissertation
01 Jul 2015
TL;DR: In this paper, the authors proposed a design approach for filtering amplifiers which removes the lossy planar matching and interconnection circuits to complete the transistor amplifiers design, and added filters resulting in a combined filtering amplifier.
Abstract: Terahertz (THz) wireless communication systems over 300 GHz can offer broad bandwidth, but they have limitations, such as high precision fabrication requirements, high fabrication cost and lossy system components. This thesis introduces a THz communication system concept based on low-cost and high precision micromachining techniques, also a new design approach to achieve a low loss system for THz communication components and systems. In order to minimise the components and systems losses, this thesis proposes a design approach for filtering amplifiers which removes the lossy planar matching and interconnection circuits to complete the transistor amplifiers design. The technique also adds filters resulting in a combined filtering amplifier. To enable this, an analytical design method for filtering amplifiers based on the conventional passive coupling matrix for filters is expanded for the filtering amplifiers. Novel coupled resonator circuits, including a general transistor model for the first time is investigated and a new [\(T\)] matrix is introduced to facilitate the transistor element. Complete mathematical formulas are provided in this thesis for the coupled resonator circuits for transistor amplifiers. Two physical design examples at X band are provided in this thesis to demonstrate the usage of the novel coupling matrix with a simple mathematical synthesis. A waveguide filtering amplifier is demonstrated using waveguide resonators. This waveguide amplifier reflects the design considerations and methods for future THz amplifier developments. Good correlations between mathematical synthesis results and physical measurements are achieved for the waveguide filtering amplifier, with 3 clearly observed poles in passband, verifying the order of the filters.

1 citations


Cites background from "Low temperature reactive ion etchin..."

  • ...thick layer (50 to 2000 μm) or 3-dimensional fabrication are listed as metal coated plasmaetched silicon [82, 83], silicon deep reactive ion etching (DRIE) [79, 79, 84–87], Lithographie, Galvanoformung, Abformung (LIGA) [88–91] and SU-8 photoresist micromachining [92–95]....

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References
More filters
Proceedings ArticleDOI
07 Feb 1993
TL;DR: In this article, the etching behavior of silicon and polyimide film has been investigated and the etch selectivity was over 900 at a power density of less than 4.0 W/cm/sup 2.
Abstract: Cryogenic reactive ion etching (RIE) has been used to fabricate microstructures. The cryogenic system has a cathode stage that is temperature controlled from 0 to -140 degrees C. A magnetic field and a narrow gap between electrodes are introduced to increase plasma density. The etching behavior of silicon and polyimide film has been investigated. Directional etching was achieved at low temperature. The etch rate was increased by using Sm-Co permanent magnets and also a high flow rate of the etching gas under constant pressure. In the case of silicon wafer etching, a maximum etch rate of 1.6 mu m/min was achieved with normalized side etch of less than 0.02 at cathode temperature of -120 degrees C. Etching selectivity was over 900 at a power density of less than 4.0 W/cm/sup 2/. In the case of the polyimide film etching, normalized side etch of less than 0.01 with an etch rate of 0.8 mu m/min was achieved at -100 degrees C. The cryogenic RIE system can be used to fabricate 3-D silicon and polyimide structures with high aspect ratio. >

41 citations

Proceedings ArticleDOI
26 Jul 1993
TL;DR: A micron-sized arm which has large work space and uses reversible TiNi thin film is proposed, and the transformation characteristics as analyzed by the DSC method shows that RTiNi can be controlled around 60/spl deg/C.
Abstract: A micron-sized arm which has large work space and uses reversible TiNi thin film is proposed. The transformation characteristics as analyzed by the DSC method shows that RTiNi can be controlled around 60/spl deg/C. The design method and fabrication process for the arm are described, and the arm was fabricated on silicon wafer. It was shown that micron sized arm using three RTiNi thin films could be fabricated based on the trial fabrication of simple micron sized arm using a RTiNi thin film.

15 citations