The continuous and aggressive downscaling of conventional CMOS devices has been driving the vast growth of ICs over the last few decades. As the CMOS downscaling approaches the fundamental limits, novel device architectures such as metallic source/drain Schottky barrier MOSFET (SB-MOSFET) and SB-FinFET are probably needed to further push the ultimate downscaling. The ultimate goal of this thesis is to integrate metallic Ni1-xPtx silicide (x=0~1) source/drain into SB-MOSFET and SB-FinFET, with an emphasis on both material and processing issues related to the integration of Ni1-xPtx silicides towards competitive devices. First, the effects of both carbon (C) and nitrogen (N) on the formation and on the Schottky barrier height (SBH) of NiSi are studied. The presence of both C and N is found to improve the poor thermal stability of NiSi significantly. The present work also explores dopant segregation (DS) using B and As for the NiSi/Si contact system. The effects of C and N implantation into the Si substrate prior to the NiSi formation are examined, and it is found that the presence of C yields positive effects in helping reduce the effective SBH to 0.1-0.2 eV for both conduction polarities. In order to unveil the mechanism of SBH tuning by DS, the variation of specific contact resistivity between silicide and Si substrates by DS is monitored. The formation of a thin interfacial dipole layer at silicide/Si interface is confirmed to be the reason of SBH modification. Second, a systematic experimental study is performed for Ni1-xPtx silicide (x=0~1) films aiming at the integration into SB-MOSFET. A distinct behavior is found for the formation of Ni silicide films. Epitaxially aligned NiSi2-y films readily grow and exhibit extraordinary morphological stability up to 800 oC when the thickness of deposited Ni (tNi) <4 nm. Polycrystalline NiSi films form and tend to agglomerate at lower temperatures for thinner films for tNi≥4 nm. Such a distinct annealing behavior is absent for the formation of Pt silicide films with all thicknesses of deposited Pt. The addition of Pt into Ni supports the above observations. Surface energy is discussed as the cause responsible for the distinct behavior in phase formation and morphological stability. Finally, three different Ni-SALICIDE schemes towards a controllable NiSi-based metallic source/drain process without severe lateral encroachment of NiSi are carried out. All of them are found to be effective in controlling the lateral encroachment. Combined with DS technology, both n- and p-types of NiSi source/drain SB-MOSFETs with excellent performance are fabricated successfully. By using the reproducible sidewall transfer lithography (STL) technology developed at KTH, PtSi source/drain SB-FinFET is also realized in this thesis. With As DS, the characteristics of PtSi source/drain SB-FinFET are transformed from p-type to n-type. This thesis work places Ni1-xPtx (x=0~1) silicides SB-MOSFETs as a competitive candidate for future CMOS technology. / QC20100708 / NEMO, NANOSIL, SINANO

As scaling of CMOS technology continues, the control of parasitic source/drain (S/D) resistance (RSD) is becoming increasingly challenging. In order to control RSD, metallic source/drain MOSFETs have attracted significant attention, due to their low resistivity, abrupt junction and low temperature processing (≤700 °C). A key issue is reducing the contact resistance between metal and channel, since small Schottky barrier height (SBH) is needed to outperform doped S/D devices. A promising method to decrease the effective barrier height is dopant segregation (DS). In this work several relevant aspects of Schottky barrier (SB) contacts are investigated, both by simulation and experiment, with the goal of improving performance and understanding of SB-MOSFET technology:First, measurements of low contact resistivity are challenging, since systematic error correction is needed for extraction. In this thesis, a method is presented to determine the accuracy of extracted contact resistivity due to propagation of random measurement error.Second, using Schottky diodes, the effect of dopant segregation of beryllium (Be), bismuth (Bi), and tellurium (Te) on the SBH of NiSi is demonstrated. Further study of Be is used to analyze the mechanism of Schottky barrier lowering.Third, in order to fabricate short gate length MOSFETs, the sidewall transfer lithography process was optimized for achieving low sidewall roughness lines down to 15 nm. Ultra-thin-body (UTB) and tri-gate SB-MOSFET using PtSi S/D and As DS were demonstrated. A simulation study was conducted showing DS can be modeled by a combination of barrier lowering and doped Si extension.Finally, a new Schottky contact model was implemented in a multi-subband Monte Carlo simulator for the first time, and was used to compare doped-S/D to SB-S/D for a 17 nm gate length double gate MOSFET. The results show that a barrier of ≤ 0.15 eV is needed to comply with the specifications given by the International Technology Roadmap for Semiconductors (ITRS). / QC 20111206

The mystery surrounding serial homicide is the apparent lack of motive for the murder. No extrinsic motive such as robbery, financial gain, passion or revenge exists, as there usually is in the case of other murders. Serial homicide is a serious, worldwide problem that has received a large amount of media attention, but only a relatively small amount of scientifically based research exists on this phenomenon. Since the 1970s various models such as the psychosocial theory model, learning theory, the motivational, fantasy, neurological theory, psychiatric, post-modern, feminist and the paranormal/demonological models were used to explain the phenomenon of serial homicide. The researcher, however, states that these models do not satisfactorily address the intrapsychic/object relation development of the serial killers personality. The structure of the research project consists of analysis of the background information of two serial killers which was gathered from one semi-structured personal interview, psychometric testing (Thematic Apperception Test, Test of Object Relations and the Picture Test of Separation and Individuation) as well as from relevant literary sources. The information was interpreted using the selected psychoanalytic theory of Sigmund Freund and the object relation theory of Melanie Klein and the data was then analysed, interpreted and tested against the following research questions: “What is the intrapsychic origin of serial homicide?”; “What is the parent-child relationship like?”; “How does the parent-child relationship influence the object relations of the serial killer?”; “How does the parental relationship influence the serial killer’s interpersonal relationships?”. These questions determine the specific internalised factors that may have contributed to the eventual development of a serial killer’s personality. The research method that is employed is a qualitative, exploratory case study method. A qualitative study was selected due to the fact that there are currently not enough incarcerated serial killers in South Africa and from those incarcerated serial killers only two were willing to participate in the research. The case study method was selected because it deals with contemporary events, multiple data sources may be used and the findings can be generalised to other case studies. Data gathering was done by psychometric testing (TAT, PTSI and TOR), a semi-structured interview and other biographical information on the subjects. The data was analysed by the descriptive-dialogic case study method. The data integration method that was selected is the data integration method of the descriptive-dialogic case study method. The data was discussed in relation to the already developed theories. This implies that parallels were drawn between the processed information and the theories. Similarities and differences between the two case studies were discussed and a general overview of the intrapsychic structure of the serial killer was stated. / Dissertation (MA (Psychology))--University of Pretoria, 2006. / Psychology / unrestricted