In this work, a novel type of optical waveguide, namely two-step undercut-etching Si waveguide (TSUESW), fabricated in Si-substrate is proposed and demonstrated. All this waveguide processing is based on two step of SF6-based dry etching method. In the first step, an anisotropic etching by Reactive Ion Etching (RIE) is used to define the waveguide core. After that, an undercut etching through an isotropic etching processing Electron Cyclotron Resonance (ECR) is then utilized to decouple the optical light of the waveguide core from Si substrate. In the measurement setup, an optical propagation loss coefficient of 2.89dB/cm is obtained by extracting from Fabry-Perot oscillation, suggesting the confined optical mode in TSUESW can be realized. A tapered optical waveguide is also designed and fabricated, where the core of tapered structure is defined as widths of from 20£gm to 6£gm for optical fiber coupler. A 4.13dB/cm of loss from 700£gm long waveguide is found in such tapered waveguide. Through the nonlinear properties of Si material, a Four-Wave Mixing (FWM) behavior is observed in tapered waveguide, further confirming the optical power can be highly confined in small core of TSUESW. It also should be noted that the waveguide technology template can be processed in a Si-substrate to realize CMOS-compatible processing, avoiding high-cost Silicon-On-Insulator (SOI) technology.

Abstract In this thesis, we propose a new geometrical structure of waveguide for the application of traveling-wave electroabsorption modulator (TWEAM). As approaching to high-speed performance in TWEAM, low parasitic capacitance in the waveguide is necessary to get good microwave propagation properties. In this work, a novel processing called two-step undercut-etching the active region (UEAR) is developed to reduce the parasitic capacitance. First of all, Beam Propagation Method (BPM) is used to calculate this 2-D structure optical modes ensuring the guiding capability in such kind of waveguides. Based on an equivalent circuit model, the microwave propagation on different structures of waveguide is then investigated to decide the UEAR waveguide structure. By the selectively etching solution on InP/InGaAsP, the processing by two-step UEAR is developed to reduce the parasitic capacitance in the waveguide core. H3PO4:HCl is used to selectively etch P-InP layer on the top of InGaAsP M.Q.W. (multiple quantum wells, active region). H3PO4:H2O2:H2O is subsequently and selectively remove InGaAsP M.Q.W.s to define the waveguide core. This processing has been successfully developed. The electrical transmission measurement on this kind of TWEAM shows low reflection S11 of < -17.5dB and a low insertion loss S21 of < ¡V2.7dB from D.C. to 40GHz, indicating high microwave performance on such two-step UEAR waveguide can be achieved due to the low parasitic capacitance.

El presente trabajo busca mostrar la diferencia entre el caudal máximo diario anual y el caudal anual máximo instantáneo. Esto, porque el primero es el dato que se obtiene en la mayoría de estaciones de medición de caudal en todo el país y el segundo es el que se obtiene mediante estructuras hidráulicas que permiten medir el caudal en todo momento evitando el efecto de la socavación que genera el agua al escurrir por terrenos naturales proclives a esta. Se demostrará porque estos datos se deben considerar en la determinación de los caudales de diseño extremos de las estructuras hidráulicas. Se analizará y comparará ambos resultados y se explicará el por qué es importante trabajar con el caudal instantáneo en vez del máximo medio diario anual. Se justificará por qué a pesar de que el caudal anual máximo instantáneo es mucho más difícil de obtener, a largo plazo resulta más provechoso de utilizar. Se expondrá por qué el registro de caudal máximo diario anual el que tienen a disposición los ingenieros en la gran mayoría de ríos del litoral de nuestro país. Se demostrará que la diferencia entre ambos genera un error que representa un verdadero riesgo para el diseñador de infraestructura hídrica que basa sus cálculos en un registro que podría resultar peligroso pues puede estar subestimado. / This work seeks to show the difference between the annual maximum daily flow and the instantaneous maximum annual flow. This is because the first is the data obtained in most of the flow measurement stations throughout the country and the second is obtained by measurements of hydraulic structures that allow the flow to be measured at all times avoiding the effect of the undermining that generates water by draining through natural lands. It will be demonstrated why these data should be considered in determining the extreme design flow rates of hydraulic structures. Both results will be analyzed and compared and it will be explained why it is important to work with the instantaneous flow rate instead of the maximum annual average daily. It will be justified why although the maximum instantaneous annual flow is much more difficult to obtain, in the long term it is more profitable to use. It will be explained why the annual maximum daily flow record available to engineers in the vast majority of rivers along the coast of our country. It will be shown that the difference between the two generates an error that represents a real risk for the water infrastructure designer who bases his calculations on a record that could be dangerous and it may be underestimated. / Tesis

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21748号 / 工博第4565号 / 新制||工||1712(附属図書館) / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 大津 宏康, 准教授 PIPATPONGSA Thirapong, 教授 三村 衛 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

This thesis deals with different methods to improve the adhesion between sputtered aluminium and positive photoresist. Factors controlling the adhesion and different ways to measure the adhesion have been investigated. Different surface treatments prior to resist disposition have been investigated as well. The investigated surface treatments and adhesion measurements are compatible with the available equipment and the existing process cycle at Strand Interconnect AB. All tests were made in class 1000 clean room. All tests in this thesis were performed with MICROPOSIT S1818 SP16, which is a commercial and commonly used positive resist manufactured by Shipley. To provide sufficient adhesion on the aluminium surface some kind of surface treatment must be used. Today a wet chemical treatment is used at Strand Interconnect. In this report methods to modify the surface properties and to measure the adhesion have been investigated. The three methods to modify the aluminium surface were oxygen plasma, wet chemicals and primers and were used in this thesis. The RF power and time duration of the oxygen plasma were varied, while the temperature, gas flow and pressure were fixed. The adhesion was determined indirectly from measuring contact angles of 50 µl DI water droplets on sputtered aluminium in the wettability test as well as directly from the undercut caused by the etch fluid at the interface between the photoresist and the aluminium surface. An oxygen plasma with 200 W power for 30 s resulted in the lowest measured contact angle, which means that the resist adheres well on the surface. The angle was 2.99 degrees compared to 6.34 degrees for the wet chemical treatment used today. The same treatment also resulted in the lowest undercut, which correlates well with the result from the contact angle measurements. The measured undercut for a 25µm wide conductor was 1.41 µm, corresponding to an undercutting constant (ku) of 1410. The wet chemical surface treatment used today resulted in an undercut of 1.60 µm, equivalent to a ku of 1233. Similar results were obtained for a 15 µm wide conductor.

This paper advances a decision theoretical foundation for pricing scripts by means of a simple model of product differentiation implementing the undercut-proof equilibrium concept. We argue that while sociological factors play undoubtedly an important role, economic analysis can complement the insights from economic sociology on pricing in the primary art market. Our model analyzes the effects of the gallery's and the artist's reputation on the price the gallery charges. The results suggest that prices positively correlate with an artist's reputation and negatively correlate with a gallery's reputation. The model may therefore explain the results of recent empirical studies that have led to similar results. (author's abstract) / Series: Department of Economics Working Paper Series

<p>This thesis deals with different methods to improve the adhesion between sputtered aluminium and positive photoresist. Factors controlling the adhesion and different ways to measure the adhesion have been investigated. Different surface treatments prior to resist disposition have been investigated as well. The investigated surface treatments and adhesion measurements are compatible with the available equipment and the existing process cycle at Strand Interconnect AB. All tests were made in class 1000 clean room. All tests in this thesis were performed with MICROPOSIT S1818 SP16, which is a commercial and commonly used positive resist manufactured by Shipley. </p><p>To provide sufficient adhesion on the aluminium surface some kind of surface treatment must be used. Today a wet chemical treatment is used at Strand Interconnect. In this report methods to modify the surface properties and to measure the adhesion have been investigated. The three methods to modify the aluminium surface were oxygen plasma, wet chemicals and primers and were used in this thesis. The RF power and time duration of the oxygen plasma were varied, while the temperature, gas flow and pressure were fixed. The adhesion was determined indirectly from measuring contact angles of 50 µl DI water droplets on sputtered aluminium in the wettability test as well as directly from the undercut caused by the etch fluid at the interface between the photoresist and the aluminium surface. </p><p>An oxygen plasma with 200 W power for 30 s resulted in the lowest measured contact angle, which means that the resist adheres well on the surface. The angle was 2.99 degrees compared to 6.34 degrees for the wet chemical treatment used today. The same treatment also resulted in the lowest undercut, which correlates well with the result from the contact angle measurements. The measured undercut for a 25µm wide conductor was 1.41 µm, corresponding to an undercutting constant (k_u) of 1410. The wet chemical surface treatment used today resulted in an undercut of 1.60 µm, equivalent to a ku of 1233. Similar results were obtained for a 15 µm wide conductor.</p>

<p>The fabrication of zone plate lenses that are used for focusing X-rays relies on nanofabrication techniques such as e-beam lithography, reactive ion etching, and electroplating. The circular grating-like zone plate pattern can have a smallest half-period, a so-called zone width, of down to 20 nm while it also needs to have a height that is 5 to 10 times the zone width to have good diffraction efficiency. This high aspect ratio structuring is a very challenging field of nanofabrication.</p><p>This diploma project has focused on improving the process step of fabricating the electroplating mold by cryo-cooling the polymer during the reactive ion etching with O₂. The low temperature causes passivation of the sidewalls of the mold during etching which results in a more ideal rectangular profile of the high aspect ratio plating mold.</p><p>By etching at -100 °C, structures with highly vertical sidewalls and no undercut were realized. The experiments showed that there is a tradeoff between the anisotropy of the zone profile and the formation rate of polymer residue, so-called RIE grass. Through a proper choice of process parameters the grass could be completely removed without introducing any undercut.</p> / QC 20100414

Cette thèse porte sur la dynamique quantique dans un dcSQUID inductif. Ce dispositif est une boucle supraconductrice interrompue par deux jonctions Josephson. Sa dynamique est analogue à celle d'une particule massive évoluant dans un potentiel bidimensionnel. Dans la limite quantique, le dcSQUID se comporte comme un atome artificiel à deux degrés de liberté, contrôlé par le courant et le flux de polarisation. Dans la limite où l'inductance de la boucle est petite devant celle des jonctions, celles-ci sont fortement couplées. La dynamique du circuit est alors celle d'un oscillateur anharmonique quantique unidimensionnel. Dans la limite des deux premiers niveaux d'énergie, ce circuit est un qubit de phase. Jusqu'alors la décohérence dans ce circuit était dominée par le bruit en courant. Nous montrons, par des mesures de spectroscopie et d'oscillations cohérentes, que l'effet du bruit en courant s'annule à courant de polarisation nul, permettant une augmentation des temps de cohérence. Dans la limite où l'inductance de la boucle est grande devant celle des jonctions, la dynamique devient bidimensionnelle. Le circuit exhibe alors un spectre d'énergie riche qui peut être décrit comme celui de deux oscillateurs anharmoniques couplés, correspondant aux modes d'oscillations symétrique et antisymétrique des phases des deux jonctions. Nous mettons en évidence ce spectre par des mesures de spectroscopie et nous démontrons la manipulation cohérente des états quantiques de chaque mode. En particulier nous mettons en évidence un couplage non-linéaire entre les deux modes, dans une limite de couplage fort. Ce couplage nous permet alors d'observer des oscillations cohérentes entre les deux modes internes de cet atome artificiel. De plus, dans ce manuscrit, nous présentons une technique innovante de fabrication de jonctions métalliques par évaporations sous angles qui n'a pas recours à un pont de résine suspendu. Finalement nous proposons un modèle simple basé sur les effets de chauffage qui explique pour la première fois une anomalie récurrente observée dans les caractéristiques courant-tension des dcSQUID. / This thesis focuses on the quantum dynamics in inductive dcSQUID. This device is a superconducting loop interrupted by two Josephson junctions. Its dynamics can be described as a massive fictitious particle in a two dimensional potential. A dcSQUID behaves as an artificial atom with two degrees of freedom, controlled by current and flux bias. When the loop inductance is smaller than the Josephson inductance, the junctions are strongly coupled. The device is then described as a one dimensional quantum anharmonic oscillator. In the limit of the two lowest energy levels, a dcSQUID is a phase qubit. Until now decoherence was dominated by the current noise. We show by spectroscopic measurement and coherent oscillations measurement that the effect of the current noise vanishes at zero current bias, enabling longer coherence times. When the loop inductance is larger than the Josephson inductance, the dynamics becomes two dimensional. The device exhibits a rich energy spectrum which can be describe as the one of two coupled anharmonic oscillators, corresponding to symmetric and antisymmetric oscillations modes of the phases across each junctions. We present spectroscopic measurement of this spectrum. We demonstrate the coherent manipulation of the quantum states of each mode. We show evidence of non linear coupling between the modes, in the strong coupling regime. This coupling enables the measurement of coherent oscillations between the internal modes of this artificial atom. In addition we present a novel fabrication technique that allows metallic junction fabrication by angle evaporation without the use of suspended bridge of resist. We propose also a simple model based on heating effects that explain for the first time a frequent anomaly in the IV characteristic of dcSQUID.

The fabrication of zone plate lenses that are used for focusing X-rays relies on nanofabrication techniques such as e-beam lithography, reactive ion etching, and electroplating. The circular grating-like zone plate pattern can have a smallest half-period, a so-called zone width, of down to 20 nm while it also needs to have a height that is 5 to 10 times the zone width to have good diffraction efficiency. This high aspect ratio structuring is a very challenging field of nanofabrication. This diploma project has focused on improving the process step of fabricating the electroplating mold by cryo-cooling the polymer during the reactive ion etching with O2. The low temperature causes passivation of the sidewalls of the mold during etching which results in a more ideal rectangular profile of the high aspect ratio plating mold. By etching at -100 °C, structures with highly vertical sidewalls and no undercut were realized. The experiments showed that there is a tradeoff between the anisotropy of the zone profile and the formation rate of polymer residue, so-called RIE grass. Through a proper choice of process parameters the grass could be completely removed without introducing any undercut. / QC 20100414