Waldemar Oleszkiewicz

Characteristics of surface and film morphology in the IBAD deposition process: a Monte Carlo simulation study

In this paper, we describe a simulation of film growth process during the deposition with concurrent ion beam bombardment. We examine the process of thin films formation at the atomistic level by means of Monte Carlo (MC) methods. An MC simulation model was used in order to investigate the influence of some deposition process parameters (the angle of the ion beam, temperature of substrates as well as the kinetic energy of particles and the ion-to-atom arrival ratio) on the final morphology and quality of thin films. The mechanism of the physical aspects of film growth, interaction of energetic particles with solid surfaces, internal rearrangements of deposited adatoms were introduced into the model. The simulations were performed on a simple cubic lattice by employing the Metropolis sampling algorithm. The presented model is more complicated than the previously published study. The dislocation pining effect as well the simulated shape of the substrate surface were included into the simulations. Therefore, one can estimate better the role of the process parameters on the internal structure and surface evolution of the deposited films.

Monte Carlo modeling of the IBAD growth of the optical films

A Monte Carlo simulation model of the ion-assisted deposition process has been used in order to investigate the influence of some parameters on the final optical quality of the thin films. The simulations were performed on a simple cubic lattice with the ballistic deposition of particles. The mechanism of internal rearrangements of deposited adatoms has been introduced into the model. The results show that the angle of the ion beam as well as the kinetic energy of particles and ion-to-atom arrival ratio play an important role in the quality of the deposited films. The influence of these parameters on morphology of the films has also been discussed.

Investigation of optical properties of silicon oxynitride films deposited by RF PECVD method

Abstract In this study, the authors deposited silicon oxynitride films by Radio Frequency Plasma Enhanced Chemical Vapour Deposition (RF PECVD) method. The research explores the relationship between the deposition process parameters and the optical properties of the deposited SiOxNy films. The optical constants of SiOxNy films were measured and calculated by spectroscopic ellipsometry method. Additionally, the authors investigated the possibility of controlling the deposited film composition by the flow ratio of different gaseous precursors: ammonia (NH3), diluted silane (2%SiH4/98%N2), nitrous oxide (N2O) and nitrogen (N2). The gas mixture introduced to the working chamber during the growth of the film has the influence on the Si–O and Si–N bonds formation and the ratio between these bonds determines the refractive index of the deposited film.

The selection of gas chemistry in reactive ion etching of AlGaN/GaN heterostructures

In this study, we discuss a scope of different gas mixtures intended for reactive ion etching of AlxGa1¿xN/GaN heterostructures in relation to percentage composition of aluminum. The results of etching process are strongly dependent on the process parameters and gas mixture applied. The selected mixture of BCl3/Cl2/Ar provides a good stability of plasma and quality of etched heterostructure mesas. The test structures of AlGaN/GaN for the RIE process were grown on a c-plane sapphire in a vertical flow LP-MOVPE (low pressure Metalorganic Vapour Phase Epitaxy) system. The surface morphology and topography of mesa structures were studied using atomic force microscope working in tapping mode and scanning electron microscope. The results of etching process for intended process parameters as well as the correlation between the gas mixture, parameters and obtained mesa structures are discussed in this article.

Optical investigations of Cr and CrN layers obtained by magnetron sputtering in ion-beam-assisted deposition process (IBAD)

In the ion beam deposition process the source of material was Cr target subjected to magnetron sputtering. Cr and CrN layers deposition processes were carried out in the presence of Ar and Ar + N2 ions atmosphere. The optical investigations of Cr and CrN layers obtained by IBAD processes were made to estimate the efficiency of such modifying factor as ion beam bombardment. The optical constants n and k were determined by ellipsometry for Cr and CrN layers deposited onto grounded or negatively biased (bias voltages from 0 to 500 V) BK7 glass substrates.

Application of radio frequency inductively coupled plasma in chemical vapor deposition process of diamond-like carbon films for modification of properties of deposited films

Abstract The authors have deposited the diamond-like carbon (DLC) films by radio frequency inductively coupled plasma enhanced chemical vapor deposition (RF ICP PECVD) method. The investigated DLC films with different sp3 fraction content were deposited on polished and textured silicon substrates. The sp3 fraction content of the deposited DLC films was ranging from 35 % to 70 % and was estimated from acquired Raman scattering spectra (excitation wavelength: 325 nm and 514.5 nm). The measurements of field emission characteristics were carried out in diode configuration. Emission properties of the DLC films were calculated from Fowler-Nordheim plots. The calculated electric field enhancement factor β was ranging from 56 to 198 for the DLC films deposited on polished substrates and from 115 to 445 for films deposited on textured substrates. The surface of the DLC films was observed by scanning electron microscope (SEM) after field emission measurements. The acquired SEM images reveled that the activation of field emission from the DLC films is connected with generation of structural damage to the DLC films.

Characterization of Diamond-like Carbon (DLC) films deposited by RF ICP PECVD method

The work presents the results of a research carried out with Plasmalab Plus 100 system, manufactured by Oxford Instruments Company. The system was configured for deposition of diamond-like carbon films by ICP PECVD method. The deposition processes were carried out in CH4 or CH4/H2 atmosphere and the state of the plasma was investigated by the OES method. The RF plasma was capacitively coupled by 13.56 MHz generator with supporting ICP generator (13.56 Mhz). The deposition processes were conducted in constant value of RF generator’s power and resultant value of the DC Bias. The power values of RF generator was set at 70 W and the power values of ICP generator was set at 300 W. In this work we focus on the influence of DLC film’s thickness on optical, electrical and structural properties of the deposited DLC films. The quality of deposited DLC layers was examined by the Raman spectroscopy, AFM microscopy and spectroscopic ellipsometry. In the investigated DLC films the calculated sp3 content was ranging from 60 % to 70 %. The films were characterized by the refractive index ranging from 2.03 to 2.1 and extinction coefficient ranging from 0.09 to 0.12.

A silicon photonic quasi-crystal structure obtained by interference lithography

Photonic quasi-crystal structures have been prepared and investigated. Symmetrical patterns were fabricated by interference lithography in negative tone photoresist and transferred to silicon by reactive ion etching. Theoretical influences of pattern detail (radius of hole) on the photonic band gap have been studied. Three types of 2D photonic quasi-crystals have been prepared: 8-fold, 10-fold and 12-fold pattern. Finally, finite-difference time-domain method was used for theoretically prediction of transmission spectrum for fabricated 12-fold quasi-crystal.