"Mobility Spectrum Techniques for Determination of Multi-Carrier Transport Parameters in Advanced Semiconductor Nanostructures "
Professor Lorenzo (Laurie) Faraone
IEEE-EDS Distinguished Lecturer
Microelectronics Research Group, The University of Western Australia
For modern semiconductor multi-layer device structures containing multiple populations of distinct carrier species, conventional Hall and resistivity data acquired at a single magnetic field provide far less information than measurements as a function of magnetic field. However, the extraction of reliable and accurate individual carrier densities and corresponding mobilities from the field-dependent data can present a number of difficult challenges, which were never fully overcome by methods such as multi-carrier fitting, the mobility spectrum analysis of Beck and Anderson, or hybrid mixed-conduction analysis. In order to overcome the limitations of these methods, several groups have contributed to development of the quantitative mobility spectrum analysis (QMSA) procedure, which is now available as a commercial product. The algorithm is analogous to a fast Fourier transform, in that it transforms data from the magnetic field domain to the mobility domain. QMSA converts the field-dependent Hall and resistivity data into visually-meaningful transformed outputs comprising the conductivity density of electrons and holes in the mobility domain. In this talk, the development of QMSA will be presented, as well as practical examples of the application of QMSA to synthetic data sets and real experimental data that are representative of modern semiconductor nanoelectronic device structures. In addition, a new High Resolution MSA (HR-MSA) procedure will be introduced, which is more robust than previous algorithms, and which has the unique capability of accurately resolving fine detail in the distribution of carrier mobilities. Some recent examples will be presented on the application of HR-MSA to AlGaN/GaN 2DEG HEMT structures, nano-scale SOI structures, multi-layer compound semiconductor nanostructures, and to vertical minority carrier transport in InAs/GaSb Type-II Superlattices.
Professor Faraone is Head of the Microelectronics Research Group (MRG) at The University of Western Australia (UWA), and Director of the WA Centre for Semiconductor Optoelectronics and Microsystems (WACSOM). Prior to joining UWA in 1987, he worked primarily in the area of silicon-based microelectronics technology with RCA Labs in Princeton, NJ, USA: in particular, silicon dioxide technology, degradation and failure, as related to non-volatile memory devices and radiation-hard silicon-on-sapphire CMOS. Since joining UWA he has worked on compound semiconductor devices, including AlGaN/GaN HEMTs and 2D electron gas transport studies, HgCdTe-based infrared sensor technology, as well as MEMS technologies for infrared applications. The MRG has a vertically integrated capability in HgCdTe semiconductor MBE growth, infrared sensor array fabrication, and modelling/packaging/testing facilities. Recent research has focussed on MEMS and the infrared microspectrometer concept, which provides enhanced tuneable hyperspectral and/or multi-spectral capabilities to IR focal plane arrays. The activities at UWA also include research into laser beam induced current (LBIC) imaging, as well as mobility spectrum techniques for magneto-transport studies. This has resulted in the development of the Quantitative Mobility Spectrum Analysis (QMSA) technique that allows the transport properties of individual carriers in a multi-layer/multi-carrier semiconductor system to be determined accurately and unambiguously. Professor Faraone is a Fellow of the Australian Academy of Science and the Academy of Technological Sciences and Engineering.