Comparing resonant photon tunneling via cavity modes and Tamm plasmon polariton modes in metal-coated Bragg mirrors

Resonant photon tunneling was investigated experimentally in multilayer structures containing a high-contrast (TiO2/SiO2) Bragg mirror capped with a semitransparent gold film. Transmission via a fundamental cavity resonance was compared with transmission via the Tamm plasmon polariton resonance that appears at the interface between a metal film and a one-dimensional photonic bandgap structure. The Tamm-plasmon-mediated transmission exhibits a smaller dependence on the angle and polarization of the incident light for similar values of peak transmission, resonance wavelength, and finesse. Implications for transparent electrical contacts based on resonant tunneling structures are discussed

Growth of Functional Thin Films by HiPIMS: Fundamentals, Challenges, Applications

Thin film materials technology is the fundament of all current modern technologies such as electronics, computers, data storages, displays, mobile devices, and Internet network communications. Numerous techniques are available to grow high-quality thin films, such as chemical vapor deposition, thermal evaporation, atomic layer deposition, and sputtering. Magnetron sputtering is the most versatile technique for deposition of thin films. It can be sub-categorized to various methods such as dc magnetron sputtering (dcMS), rf magnetron sputtering (rfMS) and high power impulse magnetron sputtering (HiPIMS). This thesis presents the experimental study and the instrumental development for the advancement of the knowledge in the difference of using conventional dcMS and HiPIMS methods to grow films. The experimental study includes materials such as Mo/V superlattices, TiN, TiO2, and SiO2. New measurement methods have been developed in addition to study the early stage of the growth of thin film using in-situ resistance measurements. The advances in measurement methods consist of new high speed sampling hardwares along with LabVIEW software programmed and tested to acquire every detail of each applied HiPIMS pulse during growth. In the first experimental part, the initial stages of growth were investigated for TiN thin films. The experiment was done for both HiPIMS and dcMS on different substrates at different growth temperatures. The growth by both methods was also compared for various deposition angles. Moreover, transition of the grown films from epitaxial to texture was observed where the built-up charge on the mask changes the energy spectra of the incoming flux of materials. In the second part, the challenges for the growth of TiO2 were studied by the HiPIMS method. Systematic study of oxygen flow, frequency, and current on the plasma power were performed. A new periodic runaway of plasma was observed and characterized when oxygen partial pressure was increased to certain level. Therefore stable plasma or periodic runaway was found in a certain range of pulsing frequencies for every oxygen pressure settings. For growth of a multilayer containing a TiO2 layer, the effect of shutter operation on the growth rate and plasma stability was studied. Also, TiO2/SiO2 Bragg mirrors were grown and the behavior of resonant photon tunneling was investigated. In the third part, a HiPIMS/dcMS comparative study was performed on the growth of Mo/V metallic superlattice structures at various growth temperatures. Different combinations of the methods for growth of the superlattice were compared

Observation of a periodic runaway in the reactive Ar/O2 high power impulse magnetron sputtering discharge

This paper reports the observation of a periodic runaway of plasma to a higher density for the reactive discharge of the target material (Ti) with moderate sputter yield. Variable emission of secondary electrons, for the alternating transition of the target from metal mode to oxide mode, is understood to be the main reason for the runaway occurring periodically. Increasing the pulsing frequency can bring the target back to a metal (or suboxide) mode, and eliminate the periodic transition of the target. Therefore, a pulsing frequency interval is defined for the reactive Ar/O2 discharge in order to sustain the plasma in a runaway-free mode without exceeding the maximum power that the magnetron can tolerate

Selective Growth of B- and C-Doped SiGe Layers in Unprocessed and Recessed Si Openings for p-type Metal-Oxide-Semiconductor Field-Effect Transistors Application

This work presents the pattern dependency of the selective epitaxial growth of boron- and carbon-doped SiGe layers in recessed and unprocessed openings. The layer profile is dependent on deposition time, chip layout, and growth parameters. Carbon and boron doping compensates for the strain in SiGe layers, and when both dopants are introduced, the strain reduction is additive. The incorporation of boron and carbon in the SiGe matrix is a competitive action. The concentration of carbon decreases, whereas the boron amount increases in SiGe layers with higher Ge content. In recessed openings, the Ge content is independent of the recess depth. The strain amount in the grown layers is graded vertically, which is due to the thickness of the epilayer exceeding the critical thickness

Selective Growth of B- and C-doped SiGe Layers in Unprocessed and Recessed Si Openings for pMOSFET Application

This work presents pattern dependency of selective epitaxial growth of boron- or carbon-doped SiGe layers in recessed or unprocessed openings. The layer profile and quality of epi-layers were found to be dependent on chip layout and the growth parameters. Carbon- and boron-doping compensated the strain in SiGe layers and when both dopants are introduced the strain reduction was additive. The incorporation of boron and carbon in SiGe matrix showed to be a competitive action. The concentration of carbon decreased when the boron amount increased in SiGe layers with higher Ge content