• Journal of the Korean Vacuum Society
• /
• 제14권1호
• /
• pp.17-23
• /
• 2005

Glow discharge mass spectrometry(GDMS) was used to determine the impurity concentrations of the deposited Cu films and the 6N Cu target. Cu films were deposited on Si (100) substrates at zero substrate bias voltage and a substrate bias voltage of -50 V using a non-mass separated ion beam deposition method. Since do GDMS has a little difficulty to apply to thin films because of the accompanying non-conducting substrate, we have used an aluminum foil to cover the edge of the Cu film in order to make an electrical contact of the Cu film deposited on the non-conducting substrate. As a result, the Cu film deposited at the substrate bias voltage of -50 V showed lower impurity contents than the Cu film deposited without the substrate bias voltage although both the Cu films were contaminated during the deposition. It was found that the concentration change of each impurity in the Cu films by applying the negative substrate bias voltage is related to the difference in their ionization potentials. The purification effect by applying the negative substrate bias voltage might result from the following reasons: 1) Penning ionization and an ionization mechanism proposed in the present study, 2) difference in the kinetic energy of accelerated Cu+ ions toward the substrate with/without the negative substrate bias voltage.

• Journal of Korean Ophthalmic Optics Society
• /
• 제9권2호
• /
• pp.291-299
• /
• 2004

DLC films were deposited using the ECR-PECVD method with the fixed deposition condition, such as ECR power, methane and hydrogen gas-flow rates and deposition time, for various substrate bias voltage. We have investigated the ion bombardment effect induced by the substrate bias voltage on films during the deposition of film. The characteristic of the films were analyzed using the FTIR, Raman, and UV/Vis spectroscopy analysis shows that the amount of dehydrogenation in films was increased with the increase of substrate bias voltage and films thickness was decreased. Raman scattering analysis shows that integrated intensity ratio(ID/IG) of the D and G peak was increased as the substrate bias voltage increased and films hardness was increased. Optical transmittances of DLC film were decreased with increasing deposition time and substrate bias voltage. From these results, it can be concluded that films deposited at this experimental have the enhanced characteristics of DLC because of the ion bombardment effect on films during the deposition of film.

• Proceedings of the IEEK Conference
• /
• 대한전자공학회 1999년도 추계종합학술대회 논문집
• /
• pp.879-882
• /
• 1999

The effects of the substrate bias on the performance of programming erasing in p-channel flash memory cell have been investigated. It is found that applying positive substrate bias can improve the programming and erasing speed. This improvements can be explained by Substrate Current Induced Hot Electron Injection. From the results, we can confirm that BTB programming method is better in programming and erasing speed than CHE programming method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
• /
• pp.302-303
• /
• 2008

Nominally undoped (intrinsic) ZnO thin films were deposited by magnetron sputtering system with utilization of substrate bias on silicon at $450^{\circ}C$. Oxygen gas was selected as sputtering gas. The deposited thins were evaluated with X-ray diffraction (XRD) for their microstructure analysis and Hall effect in Van der Pauw configuration for their electrical property. The XRD shows that the magnitude and polarity of substrate bias significantly influence the microstructure and electrical properties.

• Transactions on Electrical and Electronic Materials
• /
• 제12권5호
• /
• pp.209-212
• /
• 2011

Hafnium nitride (HfN) thin films were deposited onto a silicon substrate by inductive coupled nitrogen plasma-assisted radio frequency magnetron sputtering. The films were prepared without intentional substrate heating and a substrate negative bias voltage ($-V_b$) was varied from -50 to -150 V to accelerate the effects of nitrogen ions ($N^+$) on the substrate. X-ray diffractometer patterns showed that the structure of the films was strongly affected by the negative substrate bias voltage, and thin film crystallization in the HfN (100) plane was observed under deposition conditions of -100 $V_b$ (bias voltage). Atomic force microscopy results showed that surface roughness also varied significantly with substrate bias voltage. Films deposited under conditions of -150 $V_b$ (bias voltage) exhibited higher hardness than other films.

• Journal of the Korean Vacuum Society
• /
• 제12권3호
• /
• pp.174-181
• /
• 2003

Ta diffusion barriers have been deposited on Si (100) substrate by applying a negative substrate bias voltage. The effect of the substrate bias voltage on the properties of the Ta films was investigated. In the case of the Ta films deposited without the substrate bias voltage, a columnar structure and small grains were observed distinctly, and the electrical resistivity of the deposited Ta films was very high (250 $\mu\Omega$cm). By applying the substrate bias voltage, no clear columnar structure and grain boundary were observed. The resistivity of the Ta films decreased remarkably and at a bias voltage of -125 V, reaching a minimum value of 40 $\mu\Omega$cm, which is close to that of Ta bulk (13 $\mu\Omega$cm). The thermal stability of Cu(100 mm)/Ta(50 mm)/Si structures was evaluated after annealing in H2 atmosphere for 60 min at various temperatures. The Ta films deposited by applying the substrate bias voltage were found to be stable up to $600^{\circ}C$, while the Ta films deposited without the substrate bias voltage degraded at $400^{\circ}C$.

• Korean Journal of Materials Research
• /
• 제17권11호
• /
• pp.618-621
• /
• 2007

Chromium nitride (CrN) films were deposited on silicon substrate by RF magnetron sputtering assisted by inductive coupled nitrogen plasma without intentional substrate heating. Films were deposited with different levels of bombarding energy by nitrogen ions $(N^+)$ to investigate the influence of substrate bias voltage $(V_b)$ on the growth of CrN thin films. XRD spectra showed that the crystallographic structure of CrN films was strongly affected by substrate bias voltage. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) results showed that surface roughness and grain size of the CrN films varied significantly with bias voltage. For - 80 $V_b$ depositions, the CrN films showed bigger grain sizes than those of other bias voltage conditions. The lowest surface roughness of 0.15 nm was obtained from the CrN films deposited at .130 $V_b$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• 제21권8호
• /
• pp.706-710
• /
• 2008

The substrate bias effect on the current level of SOI-MOSFETs for high temperature operation has been investigated. In this work, we demonstrate the current level of SOI-MOSFETs can be controlled at different temperatures by applying a control bias to the substrate, showing that all current levels below T=150$^{\circ}C$ can be adjusted to a constant current level. 2D numerical simulation results show that substrate bias effectively controls the current conduction; as the substrate bias effectively lower the potential of the channel, inversion carrier generation is effectively controlled and consequently a constant current conduction level is achieved up to T=150$^{\circ}C$. We also demonstrate that the device simulated in this work has same operation at any temperature below T=150$^{\circ}C$ through mixed mode simulation.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
• /
• pp.257-260
• /
• 2007

Hydrogenated amorphous silicon thin film transistors were fabricated on a flexible metal substrate. A negative voltage at a floated gate can be induced by a negative substrate bias through a capacitor between the substrate and gate electrode. This can recover the shifted-threshold voltage to an original value.

• Journal of the Korean institute of surface engineering
• /
• 제32권3호
• /
• pp.257-264
• /
• 1999

Thin reflective films are synthesized by using PVD methods with a bright metal of Al or Ag. For purposes of improving the reflectance and adhesion of such films particularly, substrate bias was applied during sputtering (namely, ion-plating) to enhance the deposition process with higher energy. And we succeeded in fabricating a quality silver film which possesses an adhesion of $85{\;}Kg/\textrm{cm}^2$ and a high reflectivity of more than 96%. Both of reflectivity and adhesion are better in case of bias sputtering as controlled than nonbias sputtering, particularly the bias of 50-100 V showed most effective. The microstructures of sample films were examined by using various equipments and the XRD spectrum in particular showed that <111> direction is the preferred growth orientation.