Choon Hwan Kim

SiO2 doped Ge2Sb2Te5 thin films with high thermal efficiency for applications in phase change random access memory

This study examined the various physical, structural and electrical properties of SiO(2) doped Ge(2)Sb(2)Te(5) (SGST) films for phase change random access memory applications. Interestingly, SGST had a layered structure (LS) resulting from the inhomogeneous distribution of SiO(2) after annealing. The physical parameters able to affect the reset current of phase change memory (I(res)) were predicted from the Joule heating and heat conservation equations. When SiO(2) was doped into GST, thermal conductivity largely decreased by ∼ 55%. The influence of SiO(2)-doping on I(res) was examined using the test phase change memory cell. I(res) was reduced by ∼ 45%. An electro-thermal simulation showed that the reduced thermal conductivity contributes to the improvement of cell efficiency as well as the reduction of I(res), while the increased dynamic resistance contributes only to the latter. The formation and presence of the LS thermal conductivity in the set state test cell after repeated switching was confirmed.

The Work Function Behavior of Aluminum-Doped Titanium Carbide Grown by Atomic Layer Deposition

The effective work function (eWF) of Al-doped titanium carbide (TiAlC) metal electrodes prepared by atomic layer deposition shows a strong dependence on the underlying gate dielectrics. The eWF of TiAlC on HfO2 shows a low value of 4.2 eV independent of the deposition temperature and process conditions, whereas that on SiO2 shifted to a midgap value of 4.7 eV, and it was sensitive to the process conditions. The mechanism underlying this TiAlC work function dependence on different gate dielectrics is investigated in detail.

Multi-wavelength Raman and photoluminescence characterization of implanted n+/p junctions under various rapid thermal annealing conditions

Arsenic (As+) implanted p-type wafers for n+ junction were prepared and annealed in a resistively heated, single wafer rapid thermal furnace in N2. The wafers were non-destructively characterized by multi-wavelength Raman spectroscopy and multi-wavelength photoluminescence (PL) spectroscopy before and after rapid thermal annealing (RTA). Sheet resistance and dopant profiles of n+/p junctions were measured using a four point probe and secondary ion mass spectroscopy (SIMS). Strong correlation among Raman, PL spectra, sheet resistance, dopant profile and RTA conditions were observed. Approximate dopant profiles, crystal quality, junction integrity, dopant activation/deactivation rates, and approximate profiles (location and density) of non-radiative recombination centers of As+ implanted wafers were successfully characterized by multi-wavelength Raman and PL measurements without making contact. Multi-wavelength Raman and PL can provide advantages as in-line, non-contact/non-destructive process and material ...

Very Low-Work-Function ALD-Erbium Carbide (ErC 2 ) Metal Electrode on High-

Erbium carbide (ErC2) prepared by atomic layer deposition (ALD) is successfully demonstrated for the first time as a novel work function (WF) metal for nMOSFET applications. The prepared ErC2 shows a very low effective WF (eWF), as low as 3.9 eV on HfO2, yet with excellent thermal stability. In addition, it did not show significant Fermi-level pinning on high-k dielectrics even after high-temperature annealing. The low eWF property of ErC2 originates from the properties of the lanthanide family, while its good thermal stability is attributed to the properties of metal carbides. ALD-ErC2 has superior conformality over other deposition methods, and thus is a strong candidate for 3-D structure devices.

K

In this study, a new polymer deposition distribution model for a two-dimensional low-k porous SiOCH trench structure during the fluorocarbon plasma etching process is described so as to investigate the bowing effect in a nanoscale trench. The model consists of three processes, namely, (1) polymer reflection, (2) ion-assisted polymer deposition, and (3) ion-assisted polymer emission. To calculate the distribution of the polymer, the polymer flux arrived at the surface points of the trench was calculated based on the model. To estimate the profile of the trench, the flux of the etchants at the point of the trench surface was also considered. The simulated etching process is based on a simple flux model, which takes into account angular distributions for ions and radicals from the sheath edge to the trench. Simulation results show that the lower section of the sidewall had a larger number of polymer particles than the other positions of the sidewall did. According to the simulated results, the sidewall bowin...