Papers by Keyword: Dielectrics

Abstract: Silicon carbide (SiC) metal-oxide semiconductor (MOS) power devices such as metal-oxide semiconductor field-effect transistors (MOSFETs) require a stable and low defect-density interface, and a high-quality dielectric, for good device performance and reliability. Notably, the interface and dielectric properties determine the threshold voltage stability, the field-effect channel mobility, and the device lifetime as limited by dielectric breakdown in both the forward on-state and reverse blocking conditions. Here we discuss the present state of SiC MOS processing and properties and point to directions for future development. Important items to address are: 1) interface passivation approaches; 2) dielectrics; 3) device design; and 4) in-depth measurements of the interface quality and reliability.

Abstract: Solid solutions of PZT ceramic at Zr/Ti ratio of 0.56/0.44 having various content of softener (La⁺³) and hardener (Sc⁺³) ions according to chemical formula (Pb_1-y La_y) (Sc_x Zr_0.56-x Ti_0.44) O₃, [y= (0.0 and 0.02); x= (0.02, 0.04 and 0.06)], were prepared via conventional solid state reaction methods. Structural and microstructural characteristics were investigated systematically. The measurements of XRD diffraction spectra showed occurring of phase transformation after doping with Sc⁺³ ions in both, PZT and PLZT ceramics, through emerging of tetragonal phase to coexist with the rhombohedral phase. Their fraction varied depending on content of Sc⁺³ ions. SEM mages display a different influence of softener and hardener ions, at 0.02 % mole, on the grain size. Doping with La⁺³ causes reduction in grain size, whereas Sc⁺³ increase the grain size. However, further increase in Sc⁺³ content in both (PZT and PZT) ceramics causes sharp decreasing in grain size. The latter feature is preferable in terms of increasing in the energy storage values.

Abstract: High-performance plastics or engineering polymers have been actively studied for various microelectronic applications as the demand for faster processing speeds increases. Taking advantage of its high Young’s modulus ideal for inter-layer dielectric applications, polyurethane (PU), a class of linearly-segmented polymer primarily made by reacting isocyanate and polyol, were deposited on borosilicate glass and p-type Si (100) substrates via spin coating method utilizing epoxidized soybean oil as a bio-polyol replacement. Optical micrographs showed that 100% ESBO-based PU coatings exhibited homogeneous and superior quality coatings in contrast to 50% ESBO-and 100% petroleum-based PU coatings as confirmed by scanning electron micrographs and EDX analysis. Based on the surface profilometry data, we found out that PU coatings with film thickness ranging from 6 μm to 28.5 μm can be achieved. FTIR-ATR analysis revealed that maintaining the stoichiometric ratio between O–H and N–C–O vibrational modes closer to unity is a vital factor to produce a high-quality PU coating regardless of the choice of substrate. The average bandgap energy of 4.35 ± 0.03 eV was estimated from the UV-vis reflectance spectra, and the electrical resistance of 10⁷–10¹⁰ orders of magnitude was measured using a two-probe method which are typical for dielectric materials. Preliminary insights about the dielectric response of the fabricated PU coatings were investigated using electrochemical impedance spectroscopy and a low κ-value of 2.749 was calculated from the Nyquist plot of the 7.9-μm thick 100% ESBO-based PU coating deposited at 6000 rpm for 45 seconds. These promising results proved that PU coatings from bio-polyols can be tailored to achieve desired coating properties that are amenable for next-generation microelectronic packaging and curable photoresists.

Abstract: The article proposes a method of studying the localized states (“traps”) in the band gap of dielectrics. The method combines both the method of current-voltage characteristics and the method of thermally stimulated currentIt is intended to use the method for analyzing the materials, in which trapping states are quasi-continuously distributed. The article gives an example of using the method for studying of the advanced polymer material - polydiphenylenephthalide. It presents calculation of values of the activation energies and the depth of the traps. The results are compared with the data obtained by traditional methods.