M.Y. Jung

Nanofabrication of a sub-wavelength size aperture using anisotropic inductively coupled plasma processing

We successfully fabricated a nano-size silicon oxide aperture using inductively coupled plasma (ICP) anisotropic etching as a potential near-field optical probe application. Several other anisotropic semiconductor processes were also utilized for sub-wavelength size aperture fabrication. Initially, a 2 μm size dot array was photolithographically patterned on an Si(100) wafer. After the formation of a hollow pyramid by anisotropic KOH etching, stress-dependent oxide growth was performed at 1000°C to give an oxide etch-mask for dry etching. Reactive ion etching by 100 W, 9 mTorr, 40 sccm Cl2 feed gas using the ICP system with a negatively biased substrate was performed in order to fabricate the nano-size aperture. After etching at the bias voltages of 500 and 540 V, the diameter of the aperture was measured to be ~ 120 and ~ 200 nm, respectively. Finally, the oxide aperture with a sub-wavelength size diameter was obtained after Si bulk micromachining.

The influence of He addition on Cl-etching procedure for Si-nanoscale structure fabrication using reactive ion etching system

Abstract Chlorine-based plasma have been often used to etch several semiconducting materials including Si and III–V materials. The chlorine plasma etching is well suited for fabrication of Si-nanoscale structures due to its good control of undercutting and etch profile. Due to some drawbacks such as trenches and damages on the etch mask from physical ion assisted etching, the Cl2/He gas mixture using a conventional reactive ion etching system was utilized and the optimization procedures were performed. Therefore, the influence of the He flow rate was examined. As the He flow increases over 30% of the total inlet gas flow, the plasma state become stable and the etch rate starts to increase. For high flow rate over 60%, the relationship between the etch depth and the etch time was observed to be nearly linear. In addition, the etch rate has been turned out to be linearly increasing with the He flow rate. With this result, the Cl2/He mixture plasma has been utilized and tested for fabrication of the deep Si sidewall and nanosize Si pillar array.

Fabrication of sub-wavelength size aperture for nearfield optical probe on cantilever

The nanosize silicon oxide aperture on the cantilever array has been successfully fabricated as a near-field optical probe. Various semiconductor processes were utilized for sub-wavelength size aperture fabrication. The anisotropic etching of the Si substrate by alkaline solutions followed by anisotropic crystal orientation-dependent oxidation, anisotropic plasma etching and isotropic oxide etching was carried out. The 3 and 4 micron size dot arrays were initially photolithographically patterned on the frontside of the Si[100] wafer. After fabrication of the V-groove shape by anisotropic TMAH etching, the oxide growth at 1000/spl deg/C was performed to have an oxide etch-mask. The oxide layer on the Si[111] plane has been utilized as an etch mask for plasma dry etching and water-diluted HF wet etching for nanosize aperture fabrication. The Au thin layer was deposited on the fabricated oxide nano-size aperture on the cantilever array. The (5/spl times/1) NSOM array with 130 nm metal aperture was successfully fabricated.

Fabrication of gated nanosize Si-tip arrays for high perveance electron beam applications

Summary form only given. Nanosize Si-tip arrays with gated electrodes have been fabricated using self-aligned method. In order to have parallel electron beam (high perveance beam) toward the anode plate, we have designed a nanosize tip array with heights of the tip slightly less than that of a gate electrode. High perveance beam is supposed to provide a better focusing of electron beams. Hence, it is important to have a high perveance electron beam for nano lithographic application.