Disk Substrate Research Articles

Influence of the Rotation Frequency of a Disk Substrate Holder on the Crystal Structure Characteristics of MOCVD-Grown GaAs Layers

The influence of the rotation frequency of a disk substrate holder on the growth mechanism and crystal structure characteristics of MOCVD-grown GaAs layers has been studied. In the frequency range of 0–400 rpm, variations have been observed in the growth mechanism and rate, as well as of crystal perfection.

Synthesis of ALD Iridium Thin Films on Silicon and Monel K-500 Steel Substrates

Iridium (Ir) thin films have been extensively investigated for a variety of applications. Ir is a potential optical material for Fresnel zone X-ray microchannel plates, and inductive grid filters. It is also a noble metal making it well suited to corrosion resistance in harsh environments Atomic Layer Deposition (ALD) is considered a special case of chemical vapor deposition (CVD) in that two different chemical precursor materials are alternately introduced into a vacuum chamber where a chemical reaction occurs on the surface of the substrate. This method of thin film growth is self-limiting and conformal and consequently results in precise layer thickness control, stoichiometry, composition, and uniformity across a large surface area. Advantages that are unique to ALD include the ability to grow conformal thin films across complex geometries, and the relatively low temperatures required to achieve film growth. In this work, iridium metal films were synthesized on silicon (Si) and Monel K-500 alloy substrates by ALD using Iridium (III) acetylacetonate known as Ir(acac)3 or [CH3COCH=C(O-)CH3]3 Ir as precursor 1, and industrial grade O2 as oxidizing reactant. The solid Ir precursor was heated to 150 °C, and the substrate temperature was varied to establish an optimum growth window. The lowest temperature in which Ir growth was found is 200 °C, and the thin film growth rate increased as a function of temperature up to 250 °C. Higher temperatures have not yet been attempted due to equipment constraints. The Monel K-500 steel alloy flat discs were cut from commercially available Monel K-500 bars of ~1 inch diameter. In this study we report on the successful synthesis of Ir films on Si and Monel K-500 substrates. Detailed characterization has been performed using X-ray diffraction (XRD) techniques, atomic force microscopy (AFM), and field emission scanning electron microscopy (FE-SEM) of samples which have been notched with focused ion beam (FIB) techniques for cross-sectional film thickness measurements as revealed in Figure 1. The polycrystalline ALD Iridium film exhibited good chemisorption and adhesion to native oxide covered Si substrates, with hydroxyl surface termination. However even with the absence of a SiO2 surface film, the ALD synthesis of Iridium metal films worked equally well on the Monel K-500 steel alloy flat disc substrates and yielded excellent surface coverage.

Calculation of the distribution of film thickness on a rotating disk substrate in a sputtering system with long plate targets

The results of calculation of the film thickness distribution of sputtered material deposited on a horizontal rotating disk substrate in a multi-cathode sputtering system with horizontal and inclined long plate targets are presented. The possibility of obtaining the high uniformity in the thickness distribution is shown, which makes it possible to recommend the similar system for use in precision optical technology.

Copper Electrodeposition from a Water-Containing Choline Chloride-Based Deep Eutectic Solvent

Ionic liquids are increasingly being used to electrodeposit metals, alloys and semiconductor materials. The popularity of these solvents arises from their desirable characteristics such as large electrochemical windows, reasonable conductivities, and good environmental compatibility. An important class of ionic liquids are deep eutectic solvents (DESs). DESs have been shown to be stable under atmospheric conditions, are non-flammable and have low vapour pressures. DESs formulated from choline chloride (ChCl) hold special promise since they are readily available at a reasonable cost. The focus of this study is on ‘ethaline’ prepared by mixing choline chloride with ethylene glycol in a 1:2 molar ratio. Although DESs have been used to electrodeposition, earlier studies have concentrated on systems with a low water content (< 0.5 wt%). This is in line with earlier studies using other ionic liquids, since water can reduce the electrochemical window. However, these DES systems are hygroscopic, and absorb water from the atmosphere unless special precautions are taken. Not only can water absorption have an adverse effect on the electrochemical window, it can also affect deposit composition and morphology. Conversely, other researchers have shown that water can protect against the anodic decomposition of the solvent itself and prevent the formation of chlorinated by-products. Information about the impact of water content on metal electrodeposition from DESs is, however, relatively scarce. The objective of this study is to understand the influence of water on the morphology of copper electrodeposited from water-containing DESs. We first examined the effect of adding various concentrations of water (3 – 15 wt%) on the stability of the solution; in particular this was obtained from the polarisation behaviour of metal deposition. It was noted that water addition affected both the limiting current for copper deposition and the deposition potential. A second series of experiments were carried out to assess how much water is absorbed by the DES depending on the storage conditions. The water content in these experiments were determined using Karl Fischer titration and NIR spectroscopy. The effect of increasing water content on copper speciation was explored using UV-Vis spectroscopy. Subsequently, Cu films were electroplated on a steel rotating disc substrate from electrolytes containing different weight percentages of water. The deposits were characterised using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). SEM images showed that the morphology of Cu deposits was also dependent on the water content of the DES. The relationship between the observed changes in electrochemical characteristics and deposit properties with increasing water content will be discussed.

High-current electron gun with a planar magnetron integrated with an explosive-emission cathode

A new high-current electron gun with plasma anode and explosive-emission cathode integrated with planar pulsed powered magnetron is described. Five hundred twelve copper wires 1 mm in diameter and 15 mm in height serve as emitters. These emitters are installed on stainless steel disc (substrate) with 3-mm distance between them. Magnetron discharge plasma provides increased ion density on the periphery of plasma anode formed by high-current Penning discharge ignited within several milliseconds after starting of the magnetron discharge. The increased on the periphery ion density improves the uniformity of high-current electron beam produced in such an electron gun.

Analysis of Processes of Mass and Heat Transport During Gas Phase Epitaxy of a Semiconductor Structures with Rotating Disk Substrate Holder in a Horizontal Reactor

Analysis of Processes of Mass and Heat Transport During Gas Phase Epitaxy of a Semiconductor Structures with Rotating Disk Substrate Holder in a Horizontal Reactor

Blue-laser scanned imaging system using positioning marks formed on an optical disk substrate

We improved the optical disk-based imaging system to make more precise images at low cost for safety enhancement applications to observe and detect micrometer-order hazardous substances collected on a large-area surface. An optical disk substrate with positioning marks is prepared, and a signal processor is developed to automatically construct an image using the marks. We successfully obtained an image of Escherichia coli dispersed on an optical disk sample surface with a laser-scanning interval of 0.40 µm in the optical disk’s radial direction; this interval is reduced from the 0.74 and 1.36 µm intervals demonstrated in our previous papers.

High-current electron gun with a planar magnetron integrated with an explosive-emission cathode

A new high-current (up to 25 kA at accelerating voltage of 10–35 kV) electron gun with plasma anode and explosive-emission cathode integrated with a planar pulsed powered magnetron is described. 189 copper wires of 1 mm in diameter and 15 mm in height serve as emitters. Emitters are installed on a stainless steel disc (substrate) with 5-mm distance between them. Planar magnetron is placed just behind the cathode substrate. Magnetron discharge plasma increases ion density on the periphery of plasma anode formed by high-current reflective (Penning) discharge ignited within several milliseconds after the start of magnetron discharge. The ion density increased on the periphery of plasma anode improves the uniformity of high-current electron beam. It was found that new electron gun can operate at working gas (argon) pressures of ∼0.06 Pa which is close to usual values. Preliminary results of testing show that proposed electron gun promises improved uniformity of the beam energy density distribution via its cross-section.

Collective transport for active matter run-and-tumble disk systems on a traveling-wave substrate.

We examine numerically the transport of an assembly of active run-and-tumble disks interacting with a traveling-wave substrate. We show that as a function of substrate strength, wave speed, disk activity, and disk density, a variety of dynamical phases arise that are correlated with the structure and net flux of disks. We find that there is a sharp transition into a state in which the disks are only partially coupled to the substrate and form a phase-separated cluster state. This transition is associated with a drop in the net disk flux, and it can occur as a function of the substrate speed, maximum substrate force, disk run time, and disk density. Since variation of the disk activity parameters produces different disk drift rates for a fixed traveling-wave speed on the substrate, the system we consider could be used as an efficient method for active matter species separation. Within the cluster phase, we find that in some regimes the motion of the cluster center of mass is in the opposite direction to that of the traveling wave, while when the maximum substrate force is increased, the cluster drifts in the direction of the traveling wave. This suggests that swarming or clustering motion can serve as a method by which an active system can collectively move against an external drift.

Effect of the ZrO2 concentration on the crystallization behavior and the mechanical properties of high-strength MgO–Al2O3–SiO2 glass–ceramics

High-strength, colorless glass–ceramics in the MgO/Al2O3/SiO2 system with high concentrations of ZrO2 and a great potential for technical application, e.g., as high-performance hard disc substrates, are investigated. ZrO2 concentrations from 6 to 9 mol% are added to a stoichiometric cordierite glass to investigate the influence of the concentration of the nucleating agent on the crystallization behavior and the mechanical properties. The phase formation and the microstructure of the glass–ceramics are studied using X-ray diffraction and scanning electron microscopy including electron backscatter diffraction. It is shown that the volume crystallization of ZrO2, a low-/high-quartz solid solution (low-/high-QSS), and spinel is accompanied by the surface crystallization of indialite. This phase offers a much smaller coefficient of thermal expansion than the other crystal phases, which may induce high compressive stresses in the surface layer of the glass–ceramics after cooling and seems to result in excellent mechanical properties of the material. Biaxial flexural strengths of up to 1 GPa were measured. Higher ZrO2 concentrations reduce the surface crystallization of indialite and decrease the mean size of the crystals resulting in a higher translucency. The volume-crystallizing phases and the mechanical properties of the glass–ceramics do not seem to be significantly affected by the analyzed ZrO2 concentrations.

Preliminary experimental research on friction characteristics of a thick gravitational casted babbit layer on steel substrate

The ability of the antifriction materials to withstand with no lubrication for a while can be a solution for the catastrophic failure of automotive journal bearings from the internal combustion engines in accidental breakdown of the oil pump. A thick layer of antifriction material (babbit) was deposited by gravitational casting on a steel disk substrate. Four tribological disk samples coated with babbit are tested against a steel shoe on Amsler tribometer at different speeds and loads in dry friction. The values of the friction coefficient versus speed and load are presented, the obtained results indicating a mild wear regime, recommending the new babbit as a possible coating for the bushes of the journal bearings in automotive internal combustion engines. Further tests must be dedicated to the establishment of the wear intensity of the steel shoe - babbit disk tribological pair, both for motor oil lubricated and dry friction conditions.

Krypton‐xenon separation properties of SAPO‐34 zeolite materials and membranes

Separation of the radioisotope 85Kr from 136Xe is an important target during used nuclear fuel recycling. We report a detailed study on the Kr and Xe adsorption, diffusion, and membrane permeation properties of the silicoaluminophosphate zeolite SAPO‐34. Adsorption and diffusion measurements on SAPO‐34 crystals indicate their potential for use in Kr‐Xe separation membranes, but also highlight competing effects of adsorption and diffusion selectivity. SAPO‐34 membranes are synthesized on α−alumina disk and tubular substrates via steam assisted conversion seeding and hydrothermal growth, and are characterized in detail. Membrane transport measurements reveal that SAPO‐34 membranes can separate Kr from Xe by molecular sieving, with Kr permeabilities around 50 Barrer and mixture selectivity of 25–30 for Kr at ambient or slight sub‐ambient conditions. The membrane transport characteristics are modeled by the Maxwell‐Stefan equations, whose predictions are in very good agreement with experiment and confirm the minimal competing effects of adsorption and diffusion. © 2016 American Institute of Chemical Engineers AIChE J, 63: 761–769, 2017

High-Performance Snsb Nanostructured Electrode Assembly for Lithium-Ion Batteries

Lithium-ion batteries as a new clean energy with high specific energy and excellent cycle performance and long life serve widely as the power source for many portable electronic devices. However, their power and energy densities need to be further increased particularly for the application in electric vehicles. It is important to develop high capacity anode materials to increase the energy density of lithium-ion batteries as the anode material is one of the key factors affect the performance of lithium-ion batteries. SnSb intermetallic alloys are attractive materials as a potential substitute for the conventional graphite anode because their theoretical capacity of SnSb alloys has been estimated to be superior to that of graphite. However, its practical use is hampered by their large volume change during alloying and de-alloying reaction with Li+, as the continuous volume change during cycling will cause the mechanical pulverization resulting in poor cyclability and cracking of the electrode. Various strategies have been brought forward to improve the cycling stability, for example, preparing thin film materials or nanostructured materials. nanostructured alloy anodes have shown an improved cycle lifetime because nanostructured alloy anodes can accommodate the large volume change and maintain the structural integrity of the electrode during the lithiation/de-lithiation process. In this paper, a nanostructured SnSb anode for Li-ion battery has been prepared by a two-step electrode design consisting of the electrochemically assisted template growth of Cu nanopillars onto a current collector followed by electrochemical plating of SnSb, there among, Cu nanopillars current collector was obtained by P. Simon's method. We try to take advantage of the nanostructuration of our electrodes to buffer the mechanical strains occurring during the cycling of tin and antimony with Li+, thanks to larger free space available for alloy–dealloying reactions, delivers a high cycle life and good power performance. Firstly, Cu nanopillars current collectors were obtained using previously reported procedure. Briefly, arrays of copper nanorods on copper disk substrate were prepared by pulsed cathodic electrodeposition through an alumina oxide membrane. The electrolytic cell assembly has been described in P. Simon's work. Secondly, Copper nanopillars were covered with SnSb by means of an electro-co-deposition process from an aqueous solution consisting of SnSO4, KSbOC4H4O6∙1/2H2O, K4P207∙l0H2O and gelatin. The SnSb coating was produced at a constant cathode current density using a two-electrode glass cell at room temperature. Cu substrate containing copper nanopillars acted as the working electrode, whereas a Pt foil served as the counter electrode. The electrodeposits were carried out for a certain deposition time in a galvanostatic mode. After SnSb electro-co-deposition, the obtained SnSb nanostructured anodes were washed with distilled water and acetone successively and then placed under argon atmosphere to avoid oxidation. The morphology, structure and composition of these anode materials were characterized by XRD, SEM and EDS, respectively. The electrochemical reaction mechanism, charge/discharge capacity and cycle performance were analyzed by various electrochemical measurements. And on this basis, we investigated the correlations between material properties and electrochemical performance of the electrode. The scanning electron microscopy (SEM) image clearly shows SnSb nanoparticles are uniformly deposited on the surface of the Cu nanopillars without any coalescence between them. This particular nanostructure is expected to be able to accommodate volume variations occurring during cycling in a lithium cell and thus result in excellent capacity retention. EDS analysis of the deposits of SnSb on Cu nanopillars current collectors gave a Sn:Sb atomic ratio of about 1: 1. The peaks of X-ray diffraction (XRD) pattern are attributed to the SnSb phase and show a rather amorphous feature. Electrochemical measurements showed that the SnSb nanostructured anodes show a relatively smooth voltage curve and a high initial coulombic efficiency of 95.7%,Quite different the curves with distinct voltage plateaus of the SnSb film electrode which SnSb deposited on a flat surface. And more importantly, the SnSb nanostructured electrode exhibited a high initial reversible storage capacity of about 738.9mAh/g and excellent capacity retention with only 10.6% decay over 30 cycles. The reversible capacity and capacity retention is high compared with the similar materials reported by other literatures. Obviously, the SnSb alloy deposited on the Cu nanopillars experiences the same internal stress as that of the SnSb alloy deposited on a flat Cu surface. In the case of the nanostructured electrode, however, the volume variations upon cycling are effectively buffered by the large free volume between the pillars, thus giving to the electrode the observed excellent capacity retention. It is anticipated that the AAO template-assisted method could also be applied to synthesize other promising nanostructured electrode materials by electrodeposition. Figure 1

Application of polystyrene disk substrates in cellular cultivation methods: generalized specimen preparation protocol for scanning electron microscopy.

Sample preparation for scanning electron microscopy (SEM) may vary by cellular type, composition and method of cultivation. It has been proposed here that a generalized method of sample preparation may be applied for the visualization of bacteria, fungi, and human cellular tissue without modification of protocol between cell types. The following protocol was developed to incorporate polystyrene disk substrates in the simplification of sample preparation for SEM and reduce the possibility of processing artefacts. The proposed method of preparation may be applied to samples grown in either liquid or solid cultural medium regardless of cell type. With the proposed protocol, centrifugation, isolation and critical point drying are not required, therefore increasing specimen integrity. The incorporation of polystyrene disks showed positive cellular adhesion and applications in SEM for bacterial, fungal and human neuronal tissue. In addition, the simplicity of the proposed protocol is highly adaptable and may be further incorporated to visually analyse the effects of antifungals, antibiotics and disease pathogenesis through pathogen-host interactions. The proposed method of specimen preparation was incorporated in either liquid or solid state growth mediums during the cultivation of the selected cellular samples and revealed great promise in the preservation and visualization under the scanning electron microscope.

NaA zeolite membranes synthesized on top of APTES-modified porous stainless steel substrates

NaA zeolite membranes were synthesized on top of both disk and tubular porous stainless steel substrates by the secondary growth method. The support seed stage was optimized, considering the seed synthesis conditions and the deposition method. The formation of the NaA zeolite on both the membrane and the residual powder collected at the bottom of the vessel after synthesis was corroborated by X-ray diffraction (XRD). Scanning electron microscopy (SEM) revealed the formation of a film with well-defined crystals with a cubic morphology characteristic of the NaA zeolite. The support modification with 3-aminopropyltriethoxysilane improved the morphology and stability of the NaA zeolite membranes synthesized on top of porous stainless steel substrates. When vacuum was applied only in the last hydrothermal synthesis stage, a smooth zeolite layer was obtained on top of porous stainless steel supports. The single gas (H2, N2, CO2 and CH4) and mixture (H2/N2 and H2/CH4) perm-selective properties of the tubular membranes were evaluated as a function of temperature and pressure. Separation factors higher than the Knudsen coefficient were obtained in all membranes. The single gas H2 and CO2 permeation flux of the membranes increased with temperature indicating a preponderance of the activated diffusion over the Knudsen diffusion. The higher H2/CO2 ideal separation factors were 7.6 and 5.6 for the more selective tubular membranes, at 453K and 100kPa.

Designing SnOx/C films via co-sputtering as anodes for all-solid-state batteries

Abstract SnO x /C composite thin films were deposited on stainless steel disc substrates by radio frequency magnetron co-sputtering. SnO x /C thin film anode samples with different tin oxide and carbon ratios were electrochemically investigated. Samples with high carbon composition showed high capacity retention and stability compared to SnO 2 -only thin film anodes. The film with high carbon content delivered an initial discharge capacity of 8990 mA h cm − 3 at a current density of 150 μA cm − 2 . In the rate capability test from 50 to 500 μA cm − 2 , the last cycle showed 58% of the 1st cycle capacity, while the other samples retained below 50% of the initial capacity. These results indicate that carbon in the thin films resulted in electric conductivity and acted as a buffer for the detrimental tin oxide volume expansion. Consequently, co-sputtering of tin oxide and carbon opens up the possibility of non-lithium anode materials. Moreover, these SnO x /C thin films can be applied as high-performance anode materials for all-solid-state batteries.

Study of Perfluoropolyether Lubricant Consumption and Recovery in Heat Assisted Magnetic Recording Using Molecular Dynamics Simulation Method

Currently, heat-assisted magnetic recording (HAMR) technology has been proposed as a method for enabling higher storage density. In this paper, the molecular dynamic simulation method was used to investigate the consumption and recovery of the lubricant perfluoropolyether (PFPE) layer under rapid heating and cooling through HAMR. A full-atom model for the 3-D slider-lubricants-disk substrate system was built for this paper. The lubricant adheres to the diamond-like carbon substrate, and the space between the slider and the lubricant is filled with helium atoms. It is found that HAMR laser heating results in the gradual consumption of the PFPE lubricant, and that the target operational temperature $T_{0}$ significantly affects the consumption of the PFPE lubricant on the disk substrate. The extent of lubricant consumption increases sharply when $T_{0}$ is above 600 K. The lubricant’s weight percentage on the disk substrate rises up again when cooling occurs. But it cannot be completely recovered. On the other hand, the bearing pressure reduces the degree of consumption of the PFPE lubricant by laser heating. However, the effect of bearing pressure on the amount of remaining PFPE lubricant becomes weak when $T_{0}$ is above 800 K.

Effects of non-spherical colloidal silica slurry on Al-NiP hard disk substrate CMP application

Spherical and non-spherical colloidal silica size and shape were characterized and its effects on aluminum alloy nickel plated (Al-NiP) hard disk substrate during chemical mechanical polishing (CMP) was investigated. Non-spherical colloidal silica slurry shows significantly higher material removal rate (MRR) with higher coefficient of friction (CoF) when compared to spherical colloidal silica of similar size. CMP evaluations on non-spherical colloidal silica slurry particle size distribution (PSD) reveal that MRR can be further increased by using wider PSD. Conventional slurry for Al-NiP hard disk substrates which use alumina–silica composite slurry induces embedded alumina thermal asperities (TA) defects which can cause reliability failure at product level. CMP comparison between conventional alumina–silica slurry and non-spherical colloidal silica slurry shows substrates polished by using non-spherical colloidal silica slurry have no embedded TA defects, lower surface roughness and lower surface defects.

Production and characterization of thin film group IIIB, IVB and rare earth hydrides by reactive evaporation

A recent short history of reactive evaporation by D. M. Mattox [History Corner—A Short History of Reactive Evaporation, SVC Bulletin (Society of Vacuum Coaters, Spring 2014), p. 50–51] describes various methods for producing oxides, nitrides, carbides, and some compounds, but hydrides were not mentioned. A study was performed in the mid-1970s at the General Electric Company Neutron Devices Department in Largo, FL, by the author to study preparation of thin film hydrides using reactive evaporation and to determine their unique characteristics and properties. Films were produced of scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), and the rare earth praseodymium (Pr), neodymium (Nd), gadolinium (Gd), dysprosium (Dy), and erbium (Er) hydrides by hot crucible filament and electron beam evaporation in atmospheres of deuterium and tritium gases. All-metal vacuum systems were used and those used with tritium were dedicated for this processing. Thin film test samples 1000 nm thick were prepared on 1.27 cm diameter molybdenum disk substrates for each occluder (i.e., an element that can react with hydrogen to form a hydride) material. Loading characteristics as determined by gas-to-metal atomic ratios, oxidation characteristics as determined by argon–sputter Auger analysis, film structure as determined by scanning electron microscope analysis, and film stress properties as determined by a double resonator technique were used to define properties of interest. Results showed hydrogen-to-metal atomic ratios varied from 1.5 to 2.0 with near maximum loading for all but Pr and Nd occluders which correlated with the oxidation levels observed, with all occluder oxidation levels being variable due to vacuum system internal processing conditions and the materials used. Surface oxide levels varied from ∼80 Å to over 1000 Å. For most films studied, results showed that a maximum loading ratio of near 2.0 and a minimum surface oxide level of ∼80 Å could be obtained with a bulk film oxygen level of ∼0.54 oxygen as determined by microprobe analysis when an evaporation rate of ∼0.313 mg/cm2 min was used in an atmosphere of D2 or T2 gas at a system deposition pressure of 1 × 10−3 Torr (1.33 × 10−1 Pa) in an evaporation time of ∼2 min. Platelet type (i.e., a film microstructure showing an overlay of flat plates with large grain sizes) film structures were observed for most films with some film mechanical properties determined (i.e., grain size and Vickers μ-hardness), and reduced stress levels were seen with initial normalized differential (tensile) stress levels being (1.0–4.0) × 108 dyne/cm2 for tritium loaded samples and (1.5 ± 0.5) × 109 dyne/cm2 for deuterium loaded samples. Also, stress aging characteristics were determined for some hydride films prepared in a radioactive tritium gas atmosphere. Tritium loading, however, had the undesirable characteristic of having to dispose of the internal processing system fixtures, which can be minimized, but the reactive evaporation technique produced desirable thin films.

Water-clock-based autonomous flow sequencing in steadily rotating centrifugal microfluidic device

In this paper, we report the demonstration of a flow sequencing method in a centrifugal microfluidic device rotated at a constant speed. The simple poly-dimethylsioxiane chip, which consists of microchannels, chambers, and vent holes, was integrated in a compact disk substrate, and multistep flow sequencing was executed by simply spinning the device at a constant rotational speed. All the triggers were controlled by a water clock using the liquid meniscus as the clock hand. The flow modes to the sample chambers were switched by switching the air supply to the sample chambers, depending of on whether the meniscus water clock was inside the channel connection (disabling air supply) or outside it (enabling air supply). A four-step flow sequence was successfully executed using two different connections of the chambers, namely, parallel connection and serial connection. Highly reproducible autonomous trigger timing with a typical error of less than 3% was achieved. Delicate adjustment of the flow sequencing by varying the channel geometry was also demonstrated. The time-scaling of the flow sequencing was accomplished by changing the viscosity of the fluid in the water clock. Additionally, a four-step flow sequencing involving a flow injection chain was successfully demonstrated by serial connection. Through combinations and further variations of these concepts, it is expected that the proposed method would be used to realize higher-order flow programs in steadily spinning centrifugal microfluidic devices.