Mao Jung Huang

Fabrication of a fuel cell electrode with a high-aspect-ratio nanostructure array

The study presents a combination of self-assembled nanosphere lithography (SANL) and photo-assisted electrochemical etching (PAECE) to cost-effectively form an arrayed nanostructure on the silicon wafer. The aspect ratio of the pores in this nanoarray fabricated through PAECE is around 22:1. Tuning the etching voltage can convert the nanopore array to a nanopillar array with an aspect ratio of about 20:1. Finally, a two-staged PAECE is used to produce a nanopillar arrays for the production of fuel cell electrodes. Its reaction current of 10.2 mA is 72.9 times higher than that obtained by a planar electrode.

Realization of ultrafast and high-quality anodic bonding using a non-contact scanning electrode

The anodic bonding technique, which is primarily used in glass to silicon wafer bonding, has been extensively used in microelectromechanical systems (MEMS) for the packaging of microsensors and microactuators. When the bonding voltage is applied, the bonded region instantly occurs at the contact point of the cathode with the glass. The geometric shape or arranged pattern of the cathode electrode significantly affects the bonding quality, particularly the gas-trapping at the bonded interface and the bonding time. This paper presents a novel anodic bonding process, in which the non-contacting and rotating electrode with radial lines is used as the cathode for scan bonding with arc-discharge assistance. The experimental results show that a bonding ratio of 99.98% and an average bonding strength of 15.45 MPa for a 4-inch silicon/glass bonded pair can be achieved in a 17 s bonding time by using a cathode electrode with eight 45 included-angle radial lines at a rotation speed of 0.45 rpm, a non-contact gap of 120 µm, a bonding voltage of 900 V and a bonding temperature of 400 °C. This ultrafast and high-quality anodic bonding has been synchronously realized under this scan bonding technique.

Development of composite vertical wet etching for silicon material

In this research, we combined the electrochemical etching (ECE) and the metal-assisted chemical etching (MACE) to develop a composite vertical etching process for silicon material and then discuss the etching results influenced by experimental parameters. The experimental results show that the developed composite etching process has faster etching rate than both electrochemical etching and metal-assisted chemical etching process. When a bias of 0.25V is applied and the catalytic material is 10nm in thickness, a 30μm-depth vertical structure can be generated which is 3 times than the structure yield by metal-assisted chemical etching.

Fabrication of silicon nanopillars array for developing PCs sensor

This study proposed the use of combined nanosphere lithography (NSL) and photo-assisted electrochemical etching (PAECE) to generate arrayed nano-pillar with high aspect ratio on silicon wafer, and then used for the application of photonic crystals (PCs) Sensor. The experiment result indicates the NSL can conveniently define nano-array and PAECE technique can effectively yield nano-pores and nano-pillars. The nano-pore, depth of 2.3 gm and diameter of 90 nm, was generated by 1 V PAECE. When the bias of PAECE was enlarged to 2.2 V, nano-pillar array was produced with 2 μm in height, 100 nm in diameter and 20:1 for aspect ratio. The PCs sensor detection platform was composed by laser of 1550 nm, precision translation stage and polarimeter. Through this high sensitive system, we can examine the small bio-molecules of plasmid by means of the polarized variation represented in Poincarè sphere coordinate system.

Submicron Patterns on Sapphire Substrate Produced by Dual Layer Photoresist Complimentary Lithography

In this study, the combined technologies of dual-layer photoresist complimentary lithography (DPCL), inductively coupled plasma-reactive ion etching (ICP-RIE) and laser direct-write lithography (LDL) are applied to produce the submicron patterns on sapphire substrates. The inorganic photoresist has almost no resistance for chlorine containing plasma and aqueous acid etching solution. However, the organic photoresist has high resistance for chlorine containing plasma and aqueous acid etching solution. Moreover, the inorganic photoresist is less etched by oxygen plasma etching process. The organic and inorganic photoresists deposit sequentially into a composite photoresist on a substrate. The DPCL takes advantages of the complementary chemical properties of organic and inorganic photoresists. We fabricated two structures with platform and non-platform structure. The non-platform structure featured structural openings, the top and bottom diameters and the depth are approximately 780 nm, 500 nm and 233 nm, respectively. The platform structure featured structural openings, the top and bottom diameters and the depth are approximately 487 nm, 288 nm and 203 nm, respectively. The precision submicron or nanoscale patterns of large etched area and patterns with high aspect ratio can be quickly produced by this technique. This technology features a low cost but high yield production technology. It has the potential applications in fabrication of micro-/nanostructures and devices for the optoelectronic industry, semiconductor industry and energy industry.

Silicon nano-column fabricated by catalytic etching for electrode of fuel cell

With advances in fabrication technologies, a number of methods can be used to create micro/nanostructures. Herein, a simple and efficient silicon nano-column array is made through self-assembled nano-sphere lithography (SANL) and catalytic etching. Moreover, we demonstrate the ability to apply this high aspect ratio structure into fuel cell electrodes. The experimental results indicate that SANL can effectively define a nano-patterned array. The highest height of nano-column is about 10µm which were formed by catalytic etching with 25 min. Furthermore, nano-column arrays with catalytic etching of and 15 min were used to produce a fuel cell electrode. Its oxidation current of 6.04 mA is 8.1 times higher than that obtained by a planar electrode.