A Study on the Control of Residual Stress of Copper Thick-Film Using 2D Nanomaterial.

With the rapid development of the electronics industry, high-density electronic devices and component mounting have gained popularity. Because of the heat generated from these devices, efficiency of the electronic parts is significantly lowered and life of various electronic devices is considerably shortened. Therefore, it is essential to efficiently dissipate the heat generated from the device to extend product life and ensure high efficiency of electronic components.

Etch characteristics of Si and TiO nanostructures using pulse biased inductively coupled plasmas.

The etch characteristics of Si and TiO nanostructures for optical devices were investigated using pulse biased inductively coupled plasmas (ICP) with SF/CF/Ar and BCl/Ar, respectively, and the results were compared with those etched using continuous wave (CW) biased ICP. By using pulse biasing compared to CW biasing in the etching of the line/pillar nanostructures with various aspect ratios, there was a reduction of the aspect ratio dependent etching (ARDE) and therefore, uniform etch depths for nanostructures with different pattern widths, as well as the improvement of the etch profiles without any notching, were obtained not only for silicon nanostructures but also for TiO nanostructures. The investigation has determined that the improvement of etch profiles and reduced ARDE effect when using pulse biasing are related to the decreased surface charging caused by neutralization of the surface and the improved radical adsorption (or etch byproduct removal) on the etched surfaces during the pulse-off period for pulse biasing compared to CW biasing.

Changes in thickness of central macula and retinal nerve fibre layer in severe hypertensive retinopathy: a 1-year longitudinal study.

Objective: To analyse the longitudinal changes in the thickness of the central macula and retinal nerve fibre layer (RNFL) in patients with hypertensive retinopathy (HTNR) using spectral-domain optical coherence tomography (SD-OCT).

Methods: This was a prospective cohort study. We studied 18 eyes of patients with HTNR of grade IV who had been followed up for more than 1 year, and 36 normal eyes (without any relevant medical history; the control group).

Plasma Characteristics Using Superimposed Dual Frequency Inductively Coupled Plasma Source for Next Generation Device Processing.

U-shaped inductively coupled plasma (ICP) source was investigated as a linear plasma source for the next generation roll-to-toll flexible display processing. For the radio frequency power to the source, the dual frequency composed of 13.56 MHz and 2 MHz was used and the effect of dual frequency to the U-shaped ICP source on the plasma density, electron temperature, and plasma uniformity was investigated.

Nano-Welding of Ag Nanowires Using Rapid Thermal Annealing for Transparent Conductive Films.

Ag nanowire (NW) films obtained by the spraying the Ag NWs on the substrates were nano-welded by rapid thermal annealing (RTA) process and the effect of RTA process on the change of sheet resistance and optical transmittance of the Ag NW films was investigated. The increased number of Ag NW sprays on the substrate decreased the sheet resistance but also decreased the optical transmittance. By the annealing for 60 sec in a nitrogen environment to 225-250 degrees C, the sheet resistance of Ag NW film could be decreased to about 50%, even though it was accompanied by the slight decrease of optical transmittance less than 5%.

Etch Properties of Amorphous Carbon Material Using RF Pulsing in the O2/N2/CHF3 Plasma.

The amorphous carbon layer (ACL), used as the hardmask for the etching of nanoscale semi-conductor materials, was etched using O2/CHF3 in addition to O2/N2 using pulsed dual-frequency capacitively coupled plasmas, and the effects of source power pulsing for different gas combinations on the characteristics of the plasmas and ACL etching were investigated. As the etch mask for ACL, a patterned SiON layer was used. The etch rates of ACL were decreased with the decrease of pulse duty percentage for both O2/N2 and O2/CHF3 due to decrease of the reactive radicals, such as F and O, with decreasing pulse duty percentage.

Surface Modification of Block Copolymer Through Sulfur Containing Plasma Treatment.

Some of the important issues of block copolymer (BCP) as an application to the potential low cost next generation lithography are thermal stability and deformation during pattern transfer process in addition to defect density, line edge/width roughness, etc. In this study, sulfur containing plasma treatment was used to modify the BCP and the effects of the plasma on the properties of plasma treated BCP were investigated. The polystyrene hole pattern obtained from polystyrene polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) was initially degraded when the polystyrene hole was annealed at 190 °C for 15 min.

Controlled MoS₂ layer etching using CF₄ plasma.

A few-layered molybdenum disulfide (MoS2) thin film grown by plasma enhanced chemical vapor deposition was etched using a CF4 inductively coupled plasma, and the possibility of controlling the MoS2 layer thickness to a monolayer of MoS2 over a large area substrate was investigated. In addition, damage and contamination of the remaining MoS2 layer surface after etching and a possible method for film recovery was also investigated. The results from Raman spectroscopy and atomic force microscopy showed that one monolayer of MoS2 was etched by exposure to a CF4 plasma for 20 s after an initial incubation time of 20 s, i.

Controlled Layer-by-Layer Etching of MoS₂.

Two-dimensional (2D) metal dichalcogenides like molybdenum disulfide (MoS2) may provide a pathway to high-mobility channel materials that are needed for beyond-complementary metal-oxide-semiconductor (CMOS) devices. Controlling the thickness of these materials at the atomic level will be a key factor in the future development of MoS2 devices. In this study, we propose a layer-by-layer removal of MoS2 using the atomic layer etching (ALET) that is composed of the cyclic processing of chlorine (Cl)-radical adsorption and argon (Ar)(+) ion-beam desorption.

Characteristics of pulsed internal inductively coupled plasma for next generation display processing.

RF pulsed plasma characteristics of inductively coupled plasma (ICP) sources operated with internal linear type antennas for the next generation display processing were investigated. By applying the rf pulse mode in the ICP source, with decreasing the rf pulse duty percentage, the average electron temperature was decreased and the plasma non-uniformity was improved with decreasing the rf pulse duty percentage. In the case of plasma uniformity, for the same time average rf power of 3 kW to the ICP source, the plasma non-uniformity was improved from 8.

Surface degradation mechanism during the fluorine-based plasma etching of a low-k material for nanoscale semiconductors.

The degradation of a low-k material surface during the exposure to plasma etching is one of the most serious problems to be solved for the realization of high speed semiconductor devices. In this study, the factors causing the degradation of a low-k material surface during the etching using fluorine-based plasma etching have been investigated by using XPS. As the plasma factors, active radicals, bombardment energy, and charge of the ions were considered and, as the low-k material, methyl silsesquioxane (MSQ) has been used.

Cyclic chlorine trap-doping for transparent, conductive, thermally stable and damage-free graphene.

We propose a novel doping method of graphene using the cyclic trap-doping method with low energy chlorine adsorption. Low energy chlorine adsorption for graphene chlorination avoided defect (D-band) formation during the doping by maintaining the π-bonding of the graphene, which affects conductivity. In addition, by trapping chlorine dopants between the graphene layers, the sheet resistance could be decreased by ∼ 88% under optimized conditions.

Graphene doping methods and device applications.

Graphene has recently been studied as a promising material to replace and enhance conventional electronic materials in various fields such as electronics, photovoltaics, sensors, etc. However, for the electronic applications of graphene prepared by various techniques such as chemical vapor deposition, chemical exfoliation, mechanical exfoliation, etc., critical limitations are found due to the defects in the graphene in addition to the absence of a semiconducting band gap.

Formation of gallium vacancies and their effects on the nanostructure of Pd/Ir/Au ohmic contact to p-type GaN.

The properties of Pd/Ir/Au ohmic metallization on p-type GaN have been investigated. Contacts annealed at 400 degrees C in O2 atmosphere demonstrated excellent ohmic characteristics with a specific contact resistivity of 1.5 x 10(-5) Omega-cm2.

Plasma treatment of thin film coated with graphene flakes for the reduction of sheet resistance.

We investigated the effects of plasma treatment on the sheet resistance of thin films spray-coated with graphene flakes on polyethylene terephthalate (PET) substrates. Thin films coated with graphene flakes show high sheet resistance due to defects within graphene edges, domains, and residual oxygen content. Cl2 plasma treatment led to decreased sheet resistance when treatment time was increased, but when thin films were treated for too long the sheet resistance increased again.

Enhanced light extraction from GaN-based vertical light-emitting diodes with a nano-roughened N-GaN surface using dual-etch.

The effect of the dual-etch surface roughening method consisting of dry etching and wet etching on the enhancement of light extraction of vertical light emitting diodes (VLEDs) is investigated. The surface of a VLED was roughened by dry etching using SiO2 spheres as the mask while a KOH solution was used for wet etching. After the surface of the VLED was roughened by the dual-etch method, the luminous efficiency of the VLED increased due to the formation of uniform, nano-scale cone shapes and the decreased flat area ratio of the total GaN surface.

Effect of multi-polar magnetic field on the properties of nanocrystalline silicon thin film deposited by internal-type inductively coupled plasma.

An internal linear-type inductively coupled plasma (ICP) source with multi-polar permanent magnets was used to deposit nanocrystalline silicon thin films on a large-area substrate (470 mm x 370 mm), and the effects of a magnetic field on the characteristics of the plasma and deposited film were investigated. By applying the magnetic field, it was possible to obtain a high-density plasma of 2.8 x 10(11) cm(-3) at 15 mTorr Ar and 4000 W of RF power, which is about 50% higher than was obtained for the source without the magnetic field.