Woon-Chun Kim

Electrical properties of Bi2Mg2∕3Nb4∕3O7 (BMN) pyrochlore thin films deposited on Pt and Cu metal at low temperatures for embedded capacitor applications

200-nm-thick BMN films were deposited on Pt∕TiO2∕SiO2∕Si and Cu∕Ti∕SiO2∕Si substrates at various temperatures by pulsed laser deposition. The dielectric constant and capacitance density of the films deposited on Pt and Cu electrodes show similar tendency with increasing deposition temperature. On the other hand, dielectric loss of the films deposited on Cu electrode varies from 0.7% to 1.3%, while dielectric loss of films on Pt constantly shows 0.2% even though the deposition temperature increases. The low value of breakdown strength in BMN films on Pt compared to films deposited on Cu electrode was attributed to the increase of surface roughness by the formation of secondary phases at interface between BMN films and Pt electrodes.

Improvement of Light Extraction Efficiency in GaN-Based Light Emitting Diodes by Random Pattern of the p-GaN Surface Using a Silica Colloidal Mask

A two-dimensional silica colloidal particle was used to etch a p-GaN surface. By treating the p-GaN surface with polyelectrolyte (PE), mono-dispersed silica colloidal particles, 500 nm in diameter, could be uniformly distributed on a 2-in. p-GaN surface. The patterns on the p-GaN surface were produced by a plasma etching process using these colloidal particles as a mask. Etching depths of 150 and 200 nm were produced on the p-GaN surface of LED samples and an increase in the optical output power of 46.7% was observed compared to a reference sample without patterns on the p-GaN surface.

Bismuth-Based Pyrochlore Thin Films Deposited at Low Temperatures for Embedded Capacitor Applications

Various bismuth-based pyrochlore films were deposited on copper clad laminate substrates at temperatures below 150 °C by pulsed laser deposition for embedded capacitor applications. The films showed smooth and dense morphologies during deposition at room temperature. Bi2Mg2/3Nb4/3O7 (BMN) pyrochlore films showed the most stable dielectric properties and leakage current behaviors as a function of film thickness and deposition temperature. The capacitance density and breakdown field of 150-nm-thick-BMN films deposited at 150 °C were approximately 325 nF/cm2 and 410 kV/cm, respectively. The BMN films showed a dielectric constant of 55, a dielectric loss of 1.6% at 100 kHz, and a leakage current density of 1×10-8 A/cm2 at an applied field of 250 kV/cm. Metal/insulator/metal (MIM) capacitors including various bismuth-based pyrochlore films are expected to be promising candidates for printed circuit board (PCB)-embedded capacitors.

Structural and Dielectric Properties of Cubic Fluorite Bi3NbO7 Thin Films As-Deposited at 298 K by PLD for Embedded Capacitor Applications

Cubic fluorite Bi 3 NbO 7 (BNO) thin films were deposited on Cu/polymer and Cu/Si(001) substrates at 298 K by pulsed laser deposition (PLD) for embedded decoupling capacitor applications. The BNO films deposited at 298 K exhibit an amorphous structure and do not show a thickness dependence of a dielectric constant. The 200 nm thick BNO films exhibit a root-mean-square roughness of 0.7 nm, a dielectric constant of 47, a dielectric loss of 0.6% at 1 MHz, and a leakage current density of approximately 1 X 10 -8 A/cm 2 at 5 V. They show a breakdown strength of about 0.25 MV/cm. The 200 nm thick BNO films deposited at 298 K are suitable for embedded decoupling capacitor applications directly on a printed circuit board.