Aizi Jin

The field emission properties of high aspect ratio diamond nanocone arrays fabricated by focused ion beam milling

Abstract High aspect ratio diamond nanocone arrays are formed on freestanding diamond film by means of focused ion beam (FIB) milling technology and hot-filament chemical vapor deposition (HFCVD) method. The structure and phase purity of an individual diamond nanocone are characterized by scanning electron microscopy (SEM) and micro-Raman spectroscopy. The result indicatesthat the diamond cones with high aspect ratio and small tip apex radius can be obtained by optimizing the parameters ofFIB milling and diamond growth. The diamond nanocone arrays were also used to study the electron field emission propertiesand electric field shielding effect, finding high emission current density, low threshold and weak shielding effect, all attributable to the high field enhancement factor and suitable cone density of the diamond nanocone emitter.

Low-energy Electron-beam Lithography of ZEP-520 Positive Resist

Low-energy electron-beam (e-beam) lithography using ZEP-520 as a positive resist has been investigated in the energy range between 0.5 and 20 keV. The interaction between electrons and ZEP-520 resist, and its effect on the exposure dose and the penetration depth of the electrons have been studied as a function of electron energy. At 10 keV ~ 20 keV energy, we were able to achieve line gratings of about 25 nm width and 80 nm pitch in ZEP-520 films of 180 nm-thickness on silicon substrate. It is found that the main limitation in achieving high resolution and dense pattern exposure at low energy is the electron forward scattering effect for thicker resist film. Using 60nm thickness of ZEP-520 resist, we have achieved 15 nm line width with 60 nm pitch grating structures

Field Emission Properties of Pt Nanopillar Arrays Formed by Focused Ion Beams Induced Deposition

In this work, the nanofabrication of Pt nanopillar arrays with various geometries as field emitters was studied and their field emission properties were measured. Pt nanopillar arrays were fabricated on Si (100) substrate by FIB assisted chemical vapor deposition (CVD) method in a FEI DB235 dual-beam system, which is based on the principle of focusing an ion beam on the surface of a substrate in an organometallic precursor gas of C9H16Pt. For obtaining the nanopillar arrays with various densities and aspect ratios, some deposition parameters such as beam energy, beam current, beam dwelling time, angle between beam and substrate, pixel overlap ratio and the flow rate of organometallic gas, and so on were changed. By optimizing the process conditions, the formation of Pt nanopillar arrays with different densities from 0 to 1 times 108/cm 2, heights from 100 nm to 3mum, and tip radius from 80 to 150 nm were controlled

High aspect ratio Pt field emitters fabricated by electron beam assisted deposition

In this work, we studied the fabrication of high aspect ratio individual Pt nanopillar as field emitters and measured their field emission properties. Pt nanopillars were fabricated by electron beams (EB) assisted chemical vapor deposition (CVD) method with a dual-beam focused ion beam (FDB) system.

Field emission properties of diamond cone arrays formed by plasma etching

In this work, we have formed diamond cone arrays by plasma etching of diamond film without masking. Diamond film was grown on Si (100) substrate by hot-filament chemical vapor deposition (HFCVD) method using the mixture of CH/sub 4/ and H/sub 2/. Scanning electrons microscopy (SEM) was used to study the morphology of as-formed diamond cone arrays. Micro Raman spectroscopy was used to characterize the phase purity of the diamond film before and after etching. Field emission properties of diamond films with different cone densities were also studied.