Heon-Ju Lee

A study on the formation and characteristics of the SiOCH composite thin films with low dielectric constant for advanced semiconductor devices

The SiOCH composite thin films were deposited on a p-type Si(100) substrate using bis-trimethylsilane (BTMSM) and O2 mixture gases by an inductively coupled plasma chemical vapor deposition (ICPCVD). High density plasma of approximately ∼1012 cm−3 is obtained at low pressure (<320 mtorr) with an RF power of approximately 300 W in the inductively coupled plasma source where the BTMSM and oxygen gases are greatly dissociated. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) spectra show that the film has SiCH3 and OH related bonds. The CH3 groups formed the void in the film and the Si atoms in the annealed sample have different chemical states from those in the deposited sample. It means that the void is formed due to the removing of OH related bonds during the annealing process. The relative dielectric constant of the annealed sample with the flow rate ratio O2/BTMSM as 0.3 at 500°C for 30 min is approximately 2.5.

The influence of carbon content in carbon-doped silicon oxide film by thermal treatment

Abstract Carbon-doped silicon oxide (SiOC) low- k dielectric film was deposited on a p-type Si(100) substrate with mixture of bis-trimethylsilylmethane (BTMSM) and oxygen by inductively coupled plasma chemical vapor deposition (ICPCVD). Electron density and electron temperature of ∼10 12 cm −3 and 1.6 eV, respectively, were obtained at low pressure (

Facile fabrication and photoelectrochemical properties of a CuO nanorod photocathode with a ZnO nanobranch protective layer

In this study, the photoelectrochemical properties of CuO/ZnO photoelectrodes fabricated with nanorod and film structures were investigated and compared, and the effect of surface morphology on their photoelectrochemical performance was discussed in detail. The experimental results demonstrated that the CuO/ZnO photoelectrode with nanorod structures showed superior photoelectrochemical properties compared to that of the photoelectrode with the film structure. The electrochemical impedance analysis and UV-vis spectroscopy results confirmed that the hierarchical nanorod-like structure of the CuO/ZnO photoelectrode was advantageous for effective light absorption, and reduced charge transfer resistance at the electrode/electrolyte interface. At the same time, the ZnO layer effectively contributed to the suppression of photocorrosion in the CuO, and the photoelectrodes with a ZnO layer demonstrated 82.13% better stability in photoelectrochemical conditions.

Effect of ion beam irradiation on the structure of ZnO films deposited by a dc arc plasmatron.

The deposition of polycrystalline ZnO film on a cold substrate was performed by using a plasmatron in rough vacuum condition. Low energy oxygen ion beam generated by a cold cathode ion source was introduced during the deposition process. The change of film property on the ion beam energy was checked. It is shown that irradiation by 200 eV ions improves crystalline structure of the film. Increasing of ion beam energy up to 400 eV leads to the degradation of a crystalline structure and decreases the deposition rate.

Some Features of Boron Isotopes Separation by the Laser-Assisted Retardation of Condensation Method in Multipass Irradiation Cell Implemented as a Resonator

More cheap production of boron isotopes is needed to provide further progress in nuclear engineering, microelectronics, and nuclear medicine. Separation of boron isotopes by laser-assisted retarded condensation scheme is considered. Continuous irradiation of steady gas flow is considered. In this case, interaction time of gas flow with laser beam (gas flow length) is desirable to make as long as possible in order to increase excitation probability. It can be provided by suitable choice of gas flow expansion conditions, such as small molar fraction of target gas in carrier gas, gas flow, and ambient small gas pressure and temperature. We propose irradiation cell design as a resonant multipass cavity. In order to estimate its length that can be used for efficient isotopes separation, we calculated laser field distribution inside the cavity for different assumed values for mirror wall reflectivities and average photo-absorption cross sections. It has been shown, that significant saving of electricity (4.2-4.6 times less) can be expected.

Formation and characteristics of the Si-O-C-H composite films with low dielectric constant deposited by O/sub 2//BTMSM-ICPCVD

Si-O-C-H composite films were deposited using a radio frequency inductively coupled plasma chemical vapor deposition (ICPCVD) system with a BTMSM precursor and oxygen gases. FTIR spectroscopy and XPS spectra were used to investigate the bonding configurations such as Si-O-Si, Si-O-C and Si-CH/sub 3/ bonds in the films. From the changes in the FTIR and XPS spectra between the as-deposited and annealing film, we infer that the attachment of the Si-O-Si ring link with CH/sub 3/ groups is useful for forming a nano-sized void in the film. It can be explained to obtain a lower dielectric constant (k=2.3).