Capacitance spectroscopy refers to techniques for characterizing the electrical properties of semiconductor materials, junctions, and interfaces, all from the dependence of device capacitance on frequency, time, temperature, and electric potential. This book includes 15 chapters written by world-recognized, leading experts in the field, academia, national institutions, and industry, divided into four sections: Physics, Instrumentation, Applications, and Emerging Techniques. The first section establishes the fundamental framework relating capacitance and its allied concepts of conductance, admittance, and impedance to the electrical and optical properties of semiconductors. The second section reviews the electronic principles of capacitance measurements used by commercial products, as well as custom apparatus. The third section details the implementation in various scientific fields and industries, such as photovoltaics and electronic and optoelectronic devices. The last section presents the latest advances in capacitance-based electrical characterization aimed at reaching nanometer-scale resolution.

This work was devoted to the experimental study of the scanning capacitance microscopy (SCM) and spectroscopy (SCS) for the mapping of the dopants in the semiconductor structures and for the characterization of thin oxides. SCM has appeared to be a very powerful technique for doping mapping as long as qualitative images are needed, for example in order to check whether fabrication steps like implantations have been correctly operated during the fabrication of devices (presence or absence of doping of a given type in a region where it should be present). When quantitativity is needed, the only way of performing a calibration of SCM images for dopant mapping seems to grow exactly the same oxide on two different samples, one being a calibration sample from which a semi-calibration curve associating doping levels and SCM signal levels will be measured and applied to the unknown sample (semi-calibration). We have shown the capabilities of SCM for dopant mapping using a series of experimental situations and test samples covering almost all frequently encountered structures in the industry of silicon microelectronics : doping staircases of p-type and n-type structures, quantum wells and p-n junctions. Qualitative images have been obtained for a wide range of doping levels between 2.e+15 at.cm-3 to 5.e+19 at.cm-3. SCM is able to detect quantum wells of ~ 7 nm width. SCM is also able to differentiate between dopants of different type (p-type or n-type). All these results confirm the usefulness of SCM as a qualitative imaging technique. We have studied the experimental parameters playing a role in the interpretation and reproducibility of SCM signal: stray light, stray capacitance, the tip-sample contact, the influence of strong electrical fields, the sample's topography, the quality and the properties of the top oxide. We have proposed solutions for eliminating all these parasitic factors and for rendering the SCM measurements reproducible and quantitative.

Dielectric spectroscopy of semiconductors (DSS) employs dielectric measuring techniques to study delayed electronic transitions in and out of localised energy levels in the forbidden gap. Horizontal transitions between levels normally take place in the volume of the material and involve relatively small changes of energy. Vertical transitions between deep levels and the free bands involve energy changes of the order of half the band gap and take place mainly in interfacial space charge regions ad at semi-conductor-metal interfaces. DSS is uniquely able to resolve the spectra of these delayed transitions and measurements on semi-insulating GaAs in the frequency range .01 - 10,000 Hz and between 90 and 380 K show that none of them conforms to the expected exponential time dependence. Measurements are reported of the dielectric response in the frequency range .01 - 10,000 Hz of Schottky diodes on n-type GaAs with aluminum metallisation, with the results revealing several important deviations from the classically expected response. The most important and unexpected phenomena are the appearance of low-frequency dispersion (LFD) and of negative capacitance, which are strongly influenced by even small (0.1V) negative capacitance, which are strongly influenced by even small (0.1V) negative and positive biases, respectively. Both phenomena are linked with interfacial processes involving some form of instability arising from structural transformations at the metal semiconductor interface.

The science and technology related to semiconductors have received significant attention for applications in various fields including microelectronics, nanophotonics, and biotechnologies. Understanding of semiconductors has advanced to such a level that we are now able to design novel system complexes before we go for the proof-of-principle experimental demonstration. This book explains the experimental setups for optical spectral analysis of semiconductors and describes the experimental methods and the basic quantum mechanical principles underlying the fast-developing nanotechnology for semiconductors. Further, it uses numerous case studies with detailed theoretical discussions and calculations to demonstrate the data analysis. Covering structures ranging from bulk to the nanoscale, it examines applications in the semiconductor industry and biomedicine. Starting from the most basic physics of geometric optics, wave optics, quantum mechanics, solid-state physics, it provides a self-contained resource on the subject for university undergraduates. The book can be further used as a toolbox for researching and developing semiconductor nanotechnology based on spectroscopy.