Eun-Su Jung

In this study, we analyzed the electrical characteristics of metal–insulator–metal (MIM) capacitors fabricated with reference to insulator (Si_xN_y) thickness and deposition condition. Si_xN_y thicknesses of 650 Å, 500 Å, and 400 Å were used with four different conditions designated as MIM (N content 1.49), NEWMIM (N content 28.1), DAMANIT (N content 1.43), and NIT (N content 0.30), deposited by controlling gas flow and RF power as a function of N content. Capacitor characteristics were evaluated mainly in terms of the relationship between leakage current and breakdown voltage (BV). Current–voltage (I–V) characterizations revealed that a higher N–H/Si–H ratio effectively suppressed trap-assisted leakage conduction and enhanced dielectric robustness under high-field stress. Among the tested conditions, the NEWMIM process demonstrated the most favorable electrical performance with highest N contents. The MIM and NEWMIM conditions proved most effective among the evaluated processes, achieving sufficient BV values (>20 V) for reliable MIM capacitor operation and proposing a process optimization framework for integrating medium-density Si_xN_y–based MIM capacitors (2 fF/µm²) with sufficiently high BV values in the future.

This study explores the effects of different passivation gases on the properties of polymers formed on aluminum (Al) sidewalls during the etching process in Al-based interconnect structures. The research compares the use of nitrogen (N₂) and ethylene diluted with helium (C₂H₄/He) as passivation gases, focusing on the resulting polymer’s composition, thickness, and strength, as well as the levels of residual chlorine post-etch. The findings reveal that using C₂H₄ leads to the formation of a thinner, weaker polymer with lower chlorine residue compared to the thicker, stronger polymer formed with N₂. Elemental analysis further highlights significant differences in carbon and oxygen content, with C₂H₄-based polymers exhibiting lower carbon and higher oxygen levels. These results underscore the critical impact of passivation gas choice on the etching process and the integrity of Al-based interconnects, offering valuable insights for optimizing metal etching processes in semiconductor manufacturing.

We examined how controlling variables in a pre-metallization Ar sputter-etching process for in situ contact-hole cleaning affects the contact-hole profile, etching rate, and substrate damage. By adjusting process parameters, we confirmed that increasing plasma power lowered the DC bias but enhanced the etching rate of SiO₂, while increasing RF power raised both, with RF power having a more pronounced effect. Higher Ar flow rate reduced etching uniformity and slightly lowered the DC bias. There was no significant difference in the amount of etching between the oxide film types, but the nitride/oxide selectivity ratio was about 1:2. Physical damage during Ar sputter-etching was closely linked to DC bias. finally, Finally, etching of the Si and CoSi₂ sublayers was performed on the device contact hole model. At this time, Si losses of up to about 31.7 Å/s occurred, and the etch speed was strongly affected by the DC bias. By optimizing the RF power and plasma power, we achieved a Si/CoSi₂ etch selectivity ratio of about 1:2.

In this study, we analyze metal–insulator–metal (MIM) capacitors with different thicknesses of SixNy film (650 Å, 500 Å, and 400 Å) and varying levels of film quality to improve their capacitance density. SixNy thicknesses of 650 Å, 500 Å, and 400 Å are used with four different conditions, designated as MIM (N content 1.49), NEWMIM (N content 28.1), DAMANIT (N content 1.43), and NIT (N content 0.30). We divide the C–V characteristics into two categories: voltage coefficient of capacitance (VCC) and temperature coefficient of capacitance (TCC). There was an overall increase in the VCC as the thickness of the SixNy film decreased, with some variation depending on the condition. However, the TCC did not vary significantly with thickness, only with condition. At the same thickness, the NIT condition yielded the highest capacitance density, while the MIM condition showed the lowest capacitance density. This difference was due to the actual thickness of the film and the variation in its k-value depending on the condition. The most influential factor for capacitance uniformity was the thickness uniformity of the SixNy film.

Nanogenerators have garnered significant interest as environmentally friendly and potential energy-harvesting systems. Nanogenerators can be broadly classified into piezo-, tribo-, and hybrid nanogenerators. The hybrid nanogenerator used in this experiment is a nanogenerator that uses both piezo and tribo effects. These hybrid nanogenerators have the potential to be used in wearable electronics, health monitoring, IoT devices, and more. In addition, the versatility of the material application in electrospinning makes it an ideal complement to hybrid nanogenerators. However, despite their potential, several experimental variables, biocompatibility, and harvesting efficiency require improvement in the research field. In particular, maximizing the output voltage of the fibers is a significant challenge. Based on this premise, this study aims to characterize hybrid nanogenerators (HNGs) with varied structures and material combinations, with a focus on identifying HNGs that exhibit superior piezoelectric- and triboelectric-induced voltage. In this study, several HNGs based on coaxial structures were fabricated via electrospinning. PVDF-HFP and PAN, known for their remarkable electrospinning properties, were used as the primary materials. Six combinations of these two materials were fabricated and categorized into homo and hetero groups based on their composition. The output voltage of the hetero group surpassed that of the homo group, primarily because of the triboelectric-induced voltage. Specifically, the overall output voltage of the hetero group was higher. In addition, the combination group with the most favorable voltage characteristics combined PVDF-HFP@PAN(BTO) and PAN hollow, boasting an output voltage of approximately 3.5 V.

With the gradual miniaturization of electronic devices and the increasing interest in wearable devices, flexible microelectronics is being actively studied. Owing to the limitations of existing battery systems corresponding to miniaturization, there is a need for flexible alternative power sources. Accordingly, energy harvesting from surrounding environmental systems using fluorinated polymers with piezoelectric properties has received significant attention. Among them, polyvinylidene fluoride (PVDF) and PVDF co-polymers have been researched as representative organo-piezoelectric materials because of their excellent piezoelectric properties, mechanical flexibility, thermal stability, and light weight. Electrospinning is an effective method for fabricating nanofibrous meshes with superior surface-to-volume ratios from polymer solutions. During electrospinning, the polymer solution is subjected to mechanical stretching and in situ poling, corresponding to an external strong electric field. Consequently, the fraction of the piezoelectric β-phase in PVDF can be improved by the electrospinning process, and enhanced harvesting output can be realized. An overview of electrospun piezoelectric fibrous meshes composed of PVDF or PVDF co-polymers to be utilized is presented, and the recent progress in enhancement methods for harvesting output, such as fiber alignment, doping with various nanofillers, and coaxial fibers, is discussed. Additionally, other applications of these meshes as sensors are reviewed.

According to Moore's law, the semiconductor industry is experiencing certain challenges in terms of adapting to highly sophisticated integrated technology. Therefore, controlling materials at the atomic scale is considered a mandatory requirement for further development. To this end, atomic layer deposition and etching skills are being increasingly researched as potential solutions. However, several considerations exist for adopting atomic technology with respect to surface analysis. This review primarily focuses on the use of Raman scattering for evaluating atomic-layered materials. Raman scattering analysis is expected to gradually expand as a semiconductor process and mass-production monitoring technology. As this can enhance the applications of this method, our review can form the basis for establishing Raman scattering analysis as a new trend for atomic-scale monitoring.