Do-Woo Kim

Work function variation of nickel silicide using an ytterbium buffer layer for Schottky barrier metal-oxide-semiconductor field-effect transistors

In this article, incorporating ytterbium into Ni-silicide using an Yb interlayer is proposed to reduce the work function of Ni-silicide for a Ni-silicided Schottky barrier diode. The proposed Ni-silicide exhibited good Schottky barrier diode characteristics owing to the reduced work function of about 0.15−0.38 eV. Even though the ytterbium layer was deposited below nickel, a ternary phase (YbxNi1−x)Si is formed at the top region of the Ni-silicide, which is believed to reduce the work function.

Magnetocrystalline anisotropy of Sm2Fe17N2.8

Abstract The intrinsic magnetic properties of Sm 2 Fe 17 N 2.8 were investigated by high-field vibrating-sample magnetometer measurements and by calculation in the temperature range 4.2–290 K. From the results, it was found that K 2 is larger than K 1 below 230 K, and K 2 makes an important contribution to the anisotropy field. The room temperature intrinsic properties of the nitride were calculated to be M s = 1270 emu/cm 3 , K 1 = 5.9 × 10 7 erg/cm 3 , K 2 = 4.1 × 10 7 erg/cm 3 and H a = 220 kOe. At 4.2 K, the nitride was found to exhibit M s = 1354 emu/cm 3 , K 2 = 7.5 × 10 7 erg/cm 3 , K 2 = 1.6 × 10 8 erg/cm 3 and H a = 580 kOe.

Highly thermal immune nitrogen-doped Ni-germanosilicide with Co/TiN double layer for nano-scale complementary metal oxide semiconductor applications

In this study, a highly thermal immune Ni–germanosilicide utilizing a 1%-nitrogen-doped nickel and a Co/TiN double capping layer is proposed for nano-scale complementary metal oxide semiconductor field effect transistors (CMOSFETs). It is shown that thermal stability of Ni–germanosilicide is improved a lot by the nitrogen incorporation in Ni–germanosilicide film using the 1%-nitrogen-doped nickel target and Co/TiN double capping layer. Even after the post-silicidation annealing at 600 °C for 30 min, low resistivity Ni–germanosilicide can be achieved. It is believed that the nitrogen atoms in 1%-nitrogen-doped nickel are incorporated in the Ni–germanosilicide during silicidation and formed a nitride compound at the grain boundaries of Ni–germanosilicide and the Ni–germanosilicide/SiGe interface.

LED Design using Resistor Network Model

A resistor network model for the horizontal AlInGaN LED was investigated, The parameters of the proposed model are extracted from the test dies and LED, The center of the P-area is the optimal position of a P-electrode by the simulation using the model. Also the optimal chip size of the LED for the new target current was investigated, Comparing the simulation and fabrication result, the errors for the forward voltage and the light power are average 0,02 V, 8 % respectively, So the proposed resistor network model with the linear forward voltage approximation and the exponential light power model are useful in the simulation for the horizontal AlInGaN LED.

Nanocrystalline Nd12Fe80B6Nb1Ga1 melt‐spun ribbon with textured surface

In Nd‐Fe‐B melt‐spun ribbon, Ga addition is found to be effective for the orientation of c axis of 2‐14‐1 grains normal to the ribbon plane even at high wheel surface velocity. A Nd12Fe80B6Nb1Ga1 melt‐spun ribbon quenched with optimum wheel surface velocity was found to have textured structure on the free‐side surface. Furthermore, this melt‐spun ribbon was composed of fine grains of about 30 nm in size which is believed to be enough to provoke intergrain exchange interaction. The remanence and energy product of the field aligned powder of this melt‐spun ribbon was about 7% and 20% higher than those of the not‐aligned powder, respectively.

Modeling of Mixed Phosphors in White Light Emitting Diode

An optical model is proposed in the white LED using phosphor and LED chip. In this paper a new model that describes the absorption rate and quantum efficiency with increasing the mixing ratio of phosphor in silicone, and the allotment of the phosphor absorption optical power in the several phosphor mixing in the silicone. Single phosphor in silicone from the optical measurement data before and after molding, the solution to get the blue optical power and the phosphor emission optical power is proposed. By these solution the absorption rate and the quantum efficiency was obtained. The model with single phosphor mixing in the silicone the validity was confirmed.

Electrical and Physical Characteristics of Nickel Silicide using Rare-Earth Metals

In this paper, we investigated electrical and physical characteristics of nickel silicide using rare-earth metals(Er, Yb, Tb, Dy), Incorporated Ytterbium into Ni-silicide is proposed to reduce work function of Ni-silicide for nickel silicided schottky barrier diode (Ni-silicided SBD). Nickel silicide makes ohmic-contact or low schottky barrier height with p-type silicon because of similar work function () in comparison with p-type silicon. However, high schottky barrier height is formed between Ni-silicide and p-type substrate by depositing thin ytterbium layer prior to Ni deposition. Even though the ytterbium is deposited below nickel, ternary phase is formed at the top and inner region of Ni-silicide, which is believed to result in reduction of work function about 0.15 - 0.38 eV.

Effect of Chamber gas Pressure on the Microstructures and Magnetic Properties of Nd12Fe77B8Cu3 Melt-Spun Ribbons

The effect of atmospheric Ar gas pressure, PAR on the magnetic properties of NdFeB melt-spun alloy has been investigated. The fraction of gas trapped area is found to decrease according to the decrease of PAR. The experimental results, however, have shown that the melt-spun ribbon fabricated under the lower PAR has the lower coercivity and remanence with poor demagnetization curve. The poor magnetic property of low PAR alloy is found due to the coarser grain size. It is considered that a low PAR results in a low pressure of trapped gas, then a low cooling rate. This is the reason why the ribbon fabricated under a low PAR has coarser grains than that fabricated under a high PAR near the gas trapped areas.