김용태 교수

We have proposed a Pt/SrBi2Ta2O9/CeO2/SiO2/Si structure for a ferroelectric gate of metal ferroelectric insulator field effect transistor. A memory window of the proposed ferroelectric gate increases as electric field applied to the SrBi2Ta2O9 layer increases, and the memory window of Pt/SrBi2Ta2O9/CeO2/SiO2/Si is relatively greater than that of Pt/SrBi2Ta2O9/SiO2/Si. As a result, the Pt/SrBi2Ta2O9(140 nm)/CeO2(25 nm)/SiO2/Si structure has sufficiently programmable memory windows from 0.9 to 2.5

Abstract A simple layered phase‐change random access memory (PRAM) cell was fabricated using the In 3 Sb 1 Te 2 alloy. The overall resistance value of the reset state was about 70 times larger than that of the set state. The resistance difference between the amorphous and crystalline state was fairly well maintained after 10 2 cycles. Interestingly, the measured current–voltage ( I – V ) curve showed three obvious steps in the crystalline state. By means of high temperature X‐ray diffractometry

The temperature coefficient of resistance (TCR) for an as-deposited RuO2.2 thin film resistor changes from −131.6 to 1007.95 ppm/°C after the annealing at 600 °C for 30 min. Typically, a near zero TCR about 0±0.12 ppm/°C can be obtained after annealing at 300 °C for 30 min in an Ar ambient. The changes of TCR from negative to positive is attributed to the grain growth of RuOx films from fine grain (30–40 Å) to a larger one (500–800 Å) during the annealing process. Rutherford backscattering spect

Crystallization temperatures, activation energies, and thermal diffusivities of In3Sb1Te2 (IST) and Ge2Sb2Te5 (GST) are investigated with a differential scanning calorimetry, a xenon laser flash, and a transmission electron microscopy. The activation energies for crystallizing the IST and the GST are 5.2 eV and 3.31 eV, respectively. The thermal diffusivity of the IST is about a half of the GST. The thermal diffusion length in the IST-phase change random access memory cell is relatively shorter

When the partial pressure ratio of WF6:NH3:H2 is 2:1:50, (111) and (200) oriented tungsten nitride (W2N) thin films can be deposited by plasma enhanced chemical vapor deposition and the resistivity of as-deposited films is 95–100 μm cm. In order to improve the adhesion of chemical vapor deposited tungsten (W) thin films, this W2N glue layer is interposed between W and Si. The acoustic emission-load graphs obtained by the scratch test method show that the adhesion strengths of W films on the W2N

Controlling the wafer temperatures from 200 to 500 °C at H2/WF6 flow ratio equal to 24, low-resistive (about 11 μΩ cm) tungsten thin films are deposited by plasma-enhanced chemical vapor deposition. The as-deposited tungsten films have (110), (200), and (211) oriented bcc structures and Auger depth profile shows that fluorine and oxygen impurities are below the detection limit of Auger electron spectroscopy.

<m1;40p>Tungsten nitride thin films are prepared with the WF6-NH3-H2 system by the plasma-enhanced chemical vapor deposition method. X-ray diffraction and Auger spectroscopy show that the crystal structure and the composition of tungsten nitride thin films grown at the WF6/NH3 ratio of 1 are β-phase W2N. The resistivity of W2N is about 190–210 μΩ cm and it is demonstrated that severe encroachment and SiO2 etching during the low-pressure chemical vapor deposition of tungsten is rema

Abstract The boundary reaction between InSb and InTe bilayers shows that In 3 Sb 1 Te 2 (IST) is formed at the InTe side first due to the diffusion of Sb atoms from InSb to InTe rather than the diffusion of Te atoms from InTe to InSb at the crystallization temperature of IST. The diffusion of Sb atoms into InTe changes the atomic configuration of InTe, which leads to small lattice distortion and a coherent boundary region for the formation of IST crystalline thin films. (© 2011 WILEY‐VCH Verlag

For over a decade, phase-change materials have been widely researched using various materials and methods. Despite efforts, the design of novel materials is nowhere near reported. In this paper, we provide the data for doping in In3SbTe2 material with doping formation energy and distortion angle at In, Sb, and Te sites. Information on the 29 dopants reduces unnecessary time cost to select the dopant for the IST material since the dopant with the positive and big formation energy should be exclud

Interface morphology and electrical properties of Pt/SrBi2Ta2O9(SBT)/CeO2/Si ferroelectric gate structure are characterized by considering the interactions among Bi, O, and Pt atoms during annealing process. It is found that the interfacial roughness of the Pt/SBT might be reduced during the annealing at 800 °C because the bottom side of the Pt electrode reacts with Bi atoms outdiffused from the SBT and the Bi–Pt alloys are molten at 765 °C, and the metallic Bi atoms are consumed by forming Bi o

Thermal behaviors of ruthenium (Ru) and ruthenium dioxide (RuO2) Schottky contacts have been compared after rapid thermal annealing at 550–900 °C for 30 s without arsenic overpressure or capping layer. Rutherford backscattering measurements and x-ray diffraction indicate that no metallurgical interactions take place between RuO2 and GaAs. I–V characteristics of RuO2 Schottky contacts reveal that barrier height increases from 0.83 to 0.85 eV even after RTA at 900 °C, in contrast with the degradat