The operation principle and main properties of a Scanning Capacitance Microscope (SCM) are described. It is called low-frequency, because in its design typical low-frequency techniques are utilised. The main attention is focused on its lateral resolution, signal-to-noise ratio and the possibility to detect dielectric losses.

Mapping the electrostatic field of a shielded microscope probe was used to calculate the stray capacitance, flux density, sensitivity and contrast obtained on a flat conducting surface, as well as on a surface covered by a thin dielectric film. The effect of dielectric losses, represented by a parallel conductance, on the detected capacitance and the resulting phase shift has been derived.

Using the results of mapping, the requirements on a SCM input stage and the possible solutions are discussed. From the point of view of frequency range and noise the best is an electrometric input stage, with input impedance represented by its capacitance.

The achieved signal-to-noise ratio of the low frequency Scanning Capacitance Microscope renders the extension of the working frequency range to lower frequencies. The input stage can be optimised for a frequency range from about 1 kHz to a few MHz, with the possibility to extend it to about 10 MHz at the cost of reduced sensitivity at the lowest frequencies.

We present a method whereby spatial variations in the resistivity of bulk conductive specimens may be detected on the same scale as the microstructural variations from which they arise. This technique, a new development of scanning tunneling potentiometry, offers significant benefits for microstructural characterization and for investigation of microstructure/resistivity relationships in metallic materials.

We discuss micromachined localized high-frequency electric (coaxial) and magnetic (loop) field probes integrated with scanning force microscopes. Our approach enables simultaneous acquisition of both field and topography in the radio frequency (RF) through millimeter-wave regime, enabling more complete characterization of materials, devices and circuits.

Recent advances in ω-k (frequency-wavenumber) interdigital dielectrometry are described. Using this technology, information about the microstructure of dielectric materials is obtained by applying to the sensor-dielectric interface a spatially periodic electric potential swept in frequency from 0.005 Hz to 10,000 Hz. The penetration depth of the electric field is proportional to the spatial wavelength of the electric potential. Application of multi-wavelength electrode arrangements allows measurement of stratified distributions of complex dielectric permittivity. Calibration techniques serve to relate the distributed dielectric properties of materials to other physical variables, such as density, porosity, cracking, lamination, and diffusion of contaminants into the material. The specific problem treated in this paper is in the measurement of moisture concentration distribution in transformer pressboard during the diffusion of water molecules from ambient transformer oil. The output of interdigital sensors is strongly influenced by the microgranularity of the material's surface. Although this dependence complicates interpretation of the measurements in some applications, the variation of the output may also be used to characterize the shape of the surface on the microscale.

This study examines natural breakdown events on organic coated AA 2024-T3 coated using Local Electrochemical Impedance (LEI) mapping (M) and spectroscopy (S). LEIM was able to identify not only different types of defects on this system, but also provided information about the kinetics and stages of development of these defects. Supportive evidence regarding the impedance characteristics of these defects was provided by Capillary Electrophoresis (CE). Data from early stages of defect development indicate that an increased impedance develops at the site. This is related to either the development of aggregated water or electrolyte, as well as corrosion product development. Direct evidence of defect healing is also provided.

Electromechanical testing involving simultaneous electrical and mechanical measurements under load was used to study the fiber-matrix interface, fiber residual stress and marcelling (fiber waviness) in carbon fiber composites. The interface study involved single fiber pull-out while the fiber-matrix contact resistivity was measured. The residual stress study involved measuring the resistance of a single fiber embedded in the matrix while the fiber was tensioned at its exposed ends. The marcelling study involved measuring the resistance of a composite in the through-thickness direction while tension was applied in the fiber direction.

This paper reports experiments in which in situ electrical resistivity measurements were used to monitor the formation of dislocations in initially dislocation-free NiAl single crystals. The electrical resistivity is found to exhibit an abrupt jump at the onset of plastic yielding. This is interpreted to result from an abrupt nucleation of a massive density of dislocations at the yield point.

The advanced method of transient microwave photoconductivity (AMTMP) represents a new method based on cavity perturbation theory, microwave photoconductivity and harmonic oscillator model analysis. AMTMP provides a direct observation of changes to the complex dielectric constant, and free and trapped electron decays can be studied separately. The results obtained for polycrystalline CdSe thin films clearly indicate that a multiple trapping model developed for amorphous materials does not provide a satisfactory description. For SI GaAs the harmonic oscillator model provides a quantitative interpretation. The limitations are discussed for the application of this method to porous Si.

InAs is a narrow band gap semiconductor with potential for such applications as IR detectors, low temperature transistors, etc‥ However, the lack of suitable substrates has hampered progress in the development of InAs based devices. In the present study, InAs was grown by Molecular Beam Epitaxy on (001) GaP substrates. Though this system has a high lattice mismatch, (∼11%), certain MBE growth conditions result in 80% relaxed InAs layers on GaP with the mismatch accommodated predominantly by 90° pure edge dislocations. Misfit dislocation microstructures were studied using Transmission Electron Microscopy. Electrical characterization using lateral conductance and Hall effect measurements were also performed. Preliminary results indicate the possibility of misfit dislocation related conductivity. The possible correlation between interface structure and electrical properties is discussed.

N+ and p+ SiGe layers were formed in the source regions of SOI MOSFETs in order to suppress the floating-body effects by means of high-dose Ge implantation. The bandgaps of the layers were evaluated by measuring the temperature dependence of the base current of the source/channel/drain lateral bipolar transistors. It has been found that the reductions of the bandgaps due to the SiGe formation by the Ge implantation were relatively small, compared to those obtained by the theoretical calculation for heavily doped SiGe. It was also found that the bandgap reduction was larger for n+ layers than that for p+ layers.

In this paper, we examine the dopant distributions in 1.8 to 4 micron-thick boron- and phosphorus-doped epitaxial silicon layers. These layers were grown by chemical vapor deposition (CVD) on arsenic-, antimony-, or boron-doped (100)- and (111)-oriented substrates. We performed doping profile studies by means of local resistivity measurements using a spreading resistance probe (SRP). Chemical profiles of the dopants were also obtained using secondary ion mass spectrometry (SIMS).

The energy distributions of gap state densities for H-terminated Si surfaces and thermally-grown SiO2/c-Si interfaces have been evaluated by total photoelectron yield spectroscopy (PYS) with a dynamic range of eight orders of magnitude which is sufficient to detect the density of states as low as 1010cm−2eV−1. It is confirmed from the threshold energies for direct and indirect photo-excitations that, for monohydride-terminated Si(111) surfaces prepared by an NH4F treatment, no significant band-bending is observable. For H-terminated n-type sample, the gap state densities of the order of 1011cm−2eV−1 were estimated in the region within 0.4 eV from the valence band edge, which may be attributable to a very little oxidation in the sample preparation. It is also found that, for as-grown 2.5nm-thick SiO2/n+ Si, there exist interface states around midgap with densities as high as ∼1012cm−2eV−1.

We have obtained Al/SiNx:H/Si and Al/SiNx:H/InP Metal-Insulator-Semiconductor devices by directly depositing silicon nitride thin films on silicon and indium phosphide wafers by the Electron Cyclotron Resonance Plasma method at 200°C. The electrical properties of the structures were first analyzed by Capacitance-Voltage measurements and Deep-Level Transient Spectroscopy (DLTS). Some discrepancies in the absolute value of the interface trap densities were found. Later on, Admittance measurements were carried out and room and low temperature conductance transients in the silicon nitride/semiconductor interfaces were found. The shape of the conductance transients varied with the frequency and temperature at which they were obtained. This behavior, as well as the previously mentioned discrepancies, are explained in terms of a disorder-induced gap-state continuum model for the interfacial defects. A perfect agreement between experiment and theory is obtained proving the validity of the model.

A Plasma enhanced CVD system was modified to place a potential screen between a plasma and a silicon wafer. Silicon dioxide from an organometallic precursor (TEOS) was deposited onto silicon wafers. In this way, any alteration of the screen potential resulted in a modified ion speed, or the removal of the ion flux incident on the wafer. The oxides films produced in this manner were analyzed by Raman spectroscopy, and both C-V and I-V techniques. The characterization results suggest an important role for Oxygen ion bombardment on the TEOS oxidation process, such as the removal of carbon compounds from the film as TEOS oxidizes. We have evidence that ion bombardment decreases the dielectric constant and increases the hysteresis of the SiOx films. A qualitative model to explain the experimental results was developed.

This work presents the analysis performed on a SiO2 film deposited from organometallic precursors with the aim of correlating their physico-chemical properties including electrical characteristics with processing variables. The characterization tools used in this study included SEM for film homogeneity; SIMS for the determination of total carbon content; FT-MS and Raman scattering spectroscopy for surface characterization. GC-MS was used to understand the electrochemical reactions taking place while performing I-V characteristics measurements.

The use of these multiple characterization techniques pointed out to deposited films with reasonable deposition characteristics but poor electrical ones. Phase segregated heterogeneity's rich in carbonatious residues influenced the degradation of the electrical characteristics.

We demonstrate the feasibility of a Ta2O5-based metal-insulator-metal (MIM) capacitor module which is integrated into the backend-of-the-line of a 0.5 μm CMOS process flow. The demonstration utilizes 6-inch wafers, sputtered Ta2O5 films with TaN and TiN electrodes, reactive ion etch (RIE) processes for defining the capacitor stack, and a metallization scheme which uses hot Al(Cu) and W plugs and a standard forming gas anneal (N2-5% H2). Acceptable electrical properties have been achieved within these processing constraints for the integrated MIM capacitor module, including specific capacitance (C/A) and leakage current density (J) of ≥ 5 fF/μm2 and ≤ 1 pA/pF-V, respectively. In addition, we compare the fundamental properties of the Ta2O5 dielectric with literature reports and point out that leakage mechanisms must be analyzed with care due to significant dielectric relaxation in the films under certain processing/measurement conditions. For the baseline integrated films, we confirm that leakage is most consistent with a Poole-Frenkel mechanism.

The resistivities of Al thin films with added Sc or Tb largely decrease at over 350 °C. They reach to 5 -7 μΩcm after annealing at 450 °C, together with the segregation of fine Al3RE (RE = Sc or Tb) metallic compounds. However, the temperatures at which resistivity starts to decrease largely are much lower for Al-SC alloy films (150 °C) than for Al-Tb ones (250 °C). Furthermore, thermal defects of hillocks or whiskers start to appear on the film surface after annealing at 200 °C and 450 °C for Al-Sc and Al-Tb alloy films, respectively. It was revealed that the further addition of Zr to these binary alloy films largely retards a large decrease of resistivities on annealing and enhances the formation of hillocks or whiskers. On the contrary, the addition of Cu to Al-Tb or Al-Sc films significantly suppresses the formation of thermal defects and shows relatively low resistivities after annealing at 350 °C.

An aluminum alloy (Al - 1.0% Si - 0.5% Cu) was anodized in nonaqueous electrolyte solutions containing propylene carbonate (PC), ethylene glycol (EG), or γ-butyrolactone (GBL) as a solvent. MIM (metal-insulator-metal) elements using these anodic films were made to evaluate their electrical properties. Leakage current of the anodic films formed in the nonaqueous solutions was lower than those formed in aqueous electrolyte solutions. These novel films are useful as a high insulating film used for a gate insulator in thin film transistor liquid crystal displays (TFT-LCD).

Novel anodized films of nitrogen-added aluminum-based alloys were proposed for use in the fabrication of gate insulators for thin-film transistors, and the effect of nitrogen addition on the anodized aluminum-based alloys was investigated. Gadolinium and neodymium were employed as alternative alloy components. The film thickness, the dielectric constant, and the roughness average of the anodized films decreased as the nitrogen content increased, and the nitrogen content was required to be lower than 20 at.%. The most improved values of the breakdown electric fields of anodized aluminum-gadolinium and aluminum-neodymium alloy were 10.1 MV/cm with 6.0 at.% nitrogen content and 9.9 MV/cm with 4.0 at.% nitrogen content, respectively. The leakage currents of the anodized films under a negative bias, which could not be suppressed by high-temperature annealing, were adequately suppressed by nitrogen addition, especially in anodized aluminum-gadolinium alloy. The current leakage of the anodized aluminum-gadolinium alloy with 6.0 at.% nitrogen content became -8E-13 A at -10 V and 150°C. This value is nearly equal to that of chemical-vapor-deposited (CVD) films.

To evaluate the thickness of different constitutive layers of a TiAl multilayer, two different experiments, based on impedance measurements on multilayers, have been performed. In the first one, the thickness of the layer is deduced from resistivity measurements, applied to a parallel resistance model. In the second one, the thickness of the layer is deduced from comparing of calculated and measured values of surface potentials.