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eingereicht von Ludwig Josef Seidl Literaturverzeichnis: Blatt 86-93 Abstract in deutscher und englischer Sprache Paris-Lodron-Universität Salzburg, Diplomarbeit, 2019 (VLID)5791878

Recognition of defects and their subsequent characterization has to be carried out on a nanoscopic level to ensure that even smallest structures with modified material properties can be evaluated. This is a trivial need due to the fact that the oncoming generation of ULSI devices will rely on device structures in a range which is aiming towards the lower nanometre regime. In the same manner, aside of this mean stream, lots of new types of devices are coming up, essentially consisting of heterostructured systems, whose structure sizes are already hitting the 1 nm barrier. Scanning probe microscopes allow a topographic evaluation of semiconductors with nm resolution already commercially. However, implementation of additional tip-specimen-interaction-mechanisms permits to extend the mere topological imaging system to a very versatile nanocharacterization tool. In this manner various modifications have been developed to investigate the electrical, electronical as well as optical, opto-electronical and last but not least thermal, mechanical properties of the specimen under test. In this paper the usability of the combination of scanning probe microscopy with scanning electron microscopy will be explained and demonstrated exemplarily on diamond.

Thermally induced stress is determined using boundary values obtained by complementary Scanning Joule Expansion Microscopy and Scanning Thermal Microscopy. The stress function is then solved with the Finite Element Method. Surface stress analysis as well as stress analysis of multilayered structures are performed in order to demonstrate the application of the developed measurement technique to reliability investigations.

Thermo-elastic properties on aluminum interconnects are characterized by Scanning Joule Expansion Microscopy and complementary finite element analyses. Temperature distributions can be obtained by the correlation of the three-dimensional thermal expansion vectors and the device structure. Vertical and lateral displacements give access to thermally induced strains, which is important for advanced failure analyses on degradation processes.

Sintering SnO(2) powder in air or under an oxygen atmosphere at different temperatures, leads to polycrystalline samples with nanostructured surface as revealed by atomic force microscopy (AFM). The thermal treatments are also responsible for the variation of the surface electrical properties, as studied by scanning spreading resistance microscopy (SSRM) and scanning tunnelling microscopy and spectroscopy (STM-STS). The surface presents a p-conductance, contrary to the n-type characteristic of the bulk, and a band gap lower than the bulk band gap (3.6 eV). The electrical behaviour at the grain boundaries and the role of oxygen are discussed. X-ray photoelectron spectroscopy (XPS) results show a higher presence of oxygen at the boundaries, which generates a shift of the Fermi level position (E(F)-E(V)) towards lower energies.

We demonstrate a scanning near-field photon emission microscope (SNPEM) for monitoring photon emission sites with spatial resolution beyond the diffraction limit. Success of SNPEM analysis strongly depends on the sensitivity of photon emission detection. We show that scattering dielectric probe (SDP) is capable of providing both sub-100 nm resolution and compatible sensitivity at emission wavelengths between 1 μm and 1.4 μm. We propose a two step fabrication method which avoids any metal coating and ensures repeatability of parameters of different probes. We also predict that fabrication of SDP from a multi-mode fiber instead of a single mode fiber can significantly improve the collection efficiency of the probe.

Two series of novel random polyfluorene copolymers containing quinoxaline units were prepared by stressing the coupling according to Yamamoto. The first series contains 2,3-bis-(4′-tert-butyl-biphenyl-4-yl)benzo[g]quinoxaline and the second series 2,3-bis-(4′-tert-butyl-biphenyl-4-yl)quinoxaline as energy accepting unit. The copolymers were identified by gel permeation chromatography, infrared spectroscopy, and nuclear magnetic resonance spectroscopy. Thermal properties were analyzed by thermal gravimetric analysis and differential scanning calorimetry revealing amorphous copolymers that are stable up to 430 °C. The morphology was investigated using atomic force microscopy. The optical properties in solutions and thin films were analyzed. Furthermore, the thin film electro-optical properties were determined in monolayer polymer light-emitting devices. Single layer devices were built with efficiencies ranging from 0.15 to 2.0 cd/A. For the random copolymers with 5 mol % benzo[g]quinoxazoline in the polyfluorene backbone some threefold efficiency enhancement from 1.1 to 3.0 cd/A was achieved by utilizing an ultra thin interlayer of poly(9,9-di-n-octylfluorene-2,7-diyl)-alt-[1,4-phenylene-(4-sec-butylphenylimino)-1,4-phenylene] between PEDOT:PSS and the emissive random copolymer layer. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4773–4785, 2007

The hole mobility and power conversion efficiency of bulk heterojunction solar cells based on P3HT-type donor polymers and the soluble fullerene derivative [6,6]-phenyl C 61 butyric acid methyl ester (PCBM) as an acceptor both show a strong sensitivity to the introduction of interchain branches into the P3HT backbones. Branched B-P3HT copolymers display a distinctly decreased hole mobility and reduced solar cell power conversion efficiency with increasing amount of interchain 3.3'-bithiophene branches within the polythiophene macromolecules. The results illustrate the primary importance of proper solid state packing towards optimum charge transport and solar cell performance.

Time resolved investigations of electric field distributions in the near-surface regions of a dynamically biased power device using spectral EBIC microscopy are introduced. The technique described provides a facility for determination of local electrical field strengths inside devices by factoring out induced currents in their spectral components. A developed setup enhances the signal to noise ratio and reduces disturbing signals up to 160 dB, offering consequently a possibility for EBIC analysis at high switching currents of the DUT. Quantitative E-field distributions at steady state device biasing conditions and variations of the field during reverse and forward recoveries are shown under operating conditions for the example of a power diode with a guard ring as a field termination structure.

The local distribution of acoustic waves generated by a locally modulated electron beam is investigated in a hybrid system consisting of an Environmental Scanning Electron Microscope (ESEM) and an Atomic Force Microscope (AFM). Depending on the modulation, different acoustic source characteristics with different near-field conditions are generated which can be used in acoustic near-field techniques, for example to detect ferroelectric domain structures.

Due to the reduction of structure sizes in modern electronic devices reliable characterization techniques are required in the nanometer range. Since the comparable wavelengths in investigation methods are larger, near-field techniques have to be used for nano-inspection allowing sub-wavelength resolution. Also many microscopy methods with static fields imply near-field approaches.

We report a straightforward two-step synthesis toward conjugated DAD-type triblock copolymers with both electron-donor (D) and electron-acceptor (A) blocks. Cyano-substituted poly(phenylenevinylene) (CN−PPV) prepolymers with two bromide end groups hereby act as the central electron-acceptor building block and are generated under Yamamoto conditions. The dibromo prepolymers are finally coupled with monobromo-terminated regioregular poly(3-hexylthiophene) (P3HT), which is selected as the electron-donor block (D). The molecular weight of the different blocks, especially the acceptor block, can be controlled by adjusting the polymerization time and the substitution pattern (degree of alkyl substitution) of the monomers. Elemental analysis, NMR, DSC, and optical spectroscopy prove that the DAD conjugated triblock copolymers. Atomic force microscopy (AFM) images of one triblock copolymer (P3HT1−HCNPPV−P3HT1) exhibit the formation of regular nanosized mesostructures in thin films. The resulting conjugated triblo...

In this work electron-beam-induced potentials are analysed theoretically and experimentally for semiconductors. A theoretical model is developed to describe the surface potential distribution produced by an electron beam. The distribution of generated carriers is calculated using semiconductor equations. This distribution causes a local change in surface potential, which is derived with the help of quasi-Fermi energies. The potential distribution is simulated using the model developed and measured with a scanning probe microscope (SPM) built inside a scanning electron microscope (SEM), for different samples, for different beam excitations and for different cantilever voltages of SPM. In the end, some fields of application are shown where material properties can be determined using an SEM/SPM hybrid system.

A resistive probe based scanning thermal microscope (SThM) has been used to perform complementary near field thermal measurements on the surface of a thin semiconductor membrane. This thin structure is part of a micromachined thermal rf power sensor and includes an integrated resistive heater used as an absorbing element for the input power. The resulting 2D surface temperature distribution and the 2D thermal wave propagation characteristic were determined. Considering the thermal wave behaviour at near field conditions, the local thermal conductivity of the thin membrane and the surrounding bulk material was investigated by usage of the 3 ω -method.