Jai Yon Ryu

A study on the formation and characteristics of the SiOCH composite thin films with low dielectric constant for advanced semiconductor devices

The SiOCH composite thin films were deposited on a p-type Si(100) substrate using bis-trimethylsilane (BTMSM) and O2 mixture gases by an inductively coupled plasma chemical vapor deposition (ICPCVD). High density plasma of approximately ∼1012 cm−3 is obtained at low pressure (<320 mtorr) with an RF power of approximately 300 W in the inductively coupled plasma source where the BTMSM and oxygen gases are greatly dissociated. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) spectra show that the film has SiCH3 and OH related bonds. The CH3 groups formed the void in the film and the Si atoms in the annealed sample have different chemical states from those in the deposited sample. It means that the void is formed due to the removing of OH related bonds during the annealing process. The relative dielectric constant of the annealed sample with the flow rate ratio O2/BTMSM as 0.3 at 500°C for 30 min is approximately 2.5.

Derivation of linewidths for optical transitions in quantum wells due to longitudinal optical phonon scattering

Utilizing the quantum statistical operator algebra technique, we derive a new absorption coefficient formula for the optical transition in a system of electrons interacting with longitudinal optical phonons in a quantum well. The electron and phonon distribution functions are included in the lineshape function. So we can explain the phonon absorptions and emissions in an organized way for all the electron transition processes. The numerical results show that the width decreases with the well width and increases with the temperature.

Calculation of Dilational and Uniaxial Shear Potentials of Ge by a State-Independent Many-Body Projection Technique

Utilizing state-independent projection operators, we present a new optical conductivity formula for cyclotron transition in the system of electrons interacting anisotropically with phonons. The line-shape factor appearing in the conductivity tensor contains the many body effects for electrons and phonons. Applying this formula, we determine the two deformation potentials (dilation potential Ξ d and uniaxial shear potential Ξ u ) of Ge in the quantum limit. By fitting the present theoretical values with the experimental data of Murase, Enjouji and Otsuka [J. Phys. Soc. Jpn. 29 (1970) 1248] and Kobori, Ohyama and Otsuka [J. Phys. Soc. Jpn. 59 (1990) 2141], we obtain Ξ u =17.0±0.6 eV and Ξ d =-10.88±0.47 eV.

Cyclotron Resonance Lineshape Function Based on the Methods of Mori and Kawabata

The cyclotron resonance lineshape function in the electron· phonon systems is obtained by using Kawabatas approach which is based on the Kubo formalism and the Mori method of calculation. The function obtained to second order in the scattering strengh is exactly the same as Choi and Chungs lineshape function in the EWC (extremely weak coupling) scheme.

Cyclotron-transition linewidths in Ge with anisotropic scattering

Utilizing the state-independent projection technique, we obtain a general formula for the cyclotron-transition linewidth for anisotropic deformation potential phonon scattering. The formula is applied to calculate the width in Ge at low temperatures. It is shown that the transition between the two lowest adjacent Landau levels makes the most contribution to the temperature and the magnetic field dependence of the width, and the result agrees better with the experiment as the higher-order contributions are included. The width increases with the magnetic field, implying that the interaction of electrons with acoustic phonons increases with the field.

Optical properties of magnetoplasmons in multiple quantum wells

Abstract Using the random-phase approximation, the density–density correlation function including intra- and inter-Landau level transitions in multiple quantum wells is obtained under magnetic fields parallel to interfaces, on the basis of a simple model of parabolic confining potentials. The Raman intensities for the bulk and surface magnetoplasmons are investigated as a function of the number of quantum wells, the ratio of the confining potential parameter to cyclotron resonance frequency, and the momentum wave vector.

The hysteretic voltage gap for a single-electron dual-junction-array trap with stray capacitances

The hysteretic voltage gap ΔV(m) - the difference between the threshold voltages for single-charge-soliton tunnelling into and escape from a single-electron dual-junction-array trap (which consists of 2N gated small junctions with equal junction capacitances C, equal stray capacitances C0, equal input gate capacitances C1, and coupling capacitance CC) through an m-junction cotunnelling process - is investigated for various charge solitons including a single electron, an exciton, and a combined soliton. Our results show that ΔV(m) has a strong dependence on m, C0/C, C1/C, CC/C, and N, and that no hysteresis loop exists beyond a critical value ηc of C0/C. For finite stray capacitance and strong coupling capacitance, the exciton can be a candidate for use in constructing more stable single-electron circuits, as in the case of no stray capacitance and weak coupling capacitance previously discussed in the literature.