Investigation of electrically active defects at the interface of high-k dielectrics and compound semiconductors

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dc.contributor.advisor Hurley, Paul K. en O'Connor, Éamon 2016-08-24T10:18:27Z 2014 2014
dc.identifier.citation O'Connor, E. 2014. Investigation of electrically active defects at the interface of high-k dielectrics and compound semiconductors. PhD Thesis, University College Cork. en
dc.identifier.endpage 170 en
dc.description.abstract As silicon based devices in integrated circuits reach the fundamental limits of dimensional scaling there is growing research interest in the use of high electron mobility channel materials, such as indium gallium arsenide (InGaAs), in conjunction with high dielectric constant (high-k) gate oxides, for Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) based devices. The motivation for employing high mobility channel materials is to reduce power dissipation in integrated circuits while also providing improved performance. One of the primary challenges to date in the field of III-V semiconductors has been the observation of high levels of defect densities at the high-k/III-V interface, which prevents surface inversion of the semiconductor. The work presented in this PhD thesis details the characterization of MOS devices incorporating high-k dielectrics on III-V semiconductors. The analysis examines the effect of modifying the semiconductor bandgap in MOS structures incorporating InxGa1-xAs (x: 0, 0.15. 0.3, 0.53) layers, the optimization of device passivation procedures designed to reduce interface defect densities, and analysis of such electrically active interface defect states for the high-k/InGaAs system. Devices are characterized primarily through capacitance-voltage (CV) and conductance-voltage (GV) measurements of MOS structures both as a function of frequency and temperature. In particular, the density of electrically active interface states was reduced to the level which allowed the observation of true surface inversion behavior in the In0.53Ga0.47As MOS system. This was achieved by developing an optimized (NH4)2S passivation, minimized air exposure, and atomic layer deposition of an Al2O3 gate oxide. An extraction of activation energies allows discrimination of the mechanisms responsible for the inversion response. Finally a new approach is described to determine the minority carrier generation lifetime and the oxide capacitance in MOS structures. The method is demonstrated for an In0.53Ga0.47As system, but is generally applicable to any MOS structure exhibiting a minority carrier response in inversion. en
dc.description.sponsorship Science Foundation Ireland (SFI Grant 07/SRC/I1172 FORME, SFI Grant 09/IN.1/I2633 INVENT) en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2014, Éamon O'Connor. en
dc.rights.uri en
dc.subject InGaAs en
dc.subject GaAs en
dc.subject MOS capacitor en
dc.subject High-k en
dc.subject Inversion en
dc.subject Interface states en
dc.subject Ammonium sulfide en
dc.title Investigation of electrically active defects at the interface of high-k dielectrics and compound semiconductors en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PHD (Engineering) en
dc.internal.availability Full text not available en
dc.description.version Accepted Version
dc.contributor.funder Science Foundation Ireland en
dc.description.status Not peer reviewed en Tyndall National Institute en
dc.check.reason This thesis is due for publication or the author is actively seeking to publish this material en
dc.check.opt-out Not applicable en
dc.thesis.opt-out false
dc.check.entireThesis Entire Thesis Restricted
dc.check.embargoformat Both hard copy thesis and e-thesis en
dc.internal.conferring Spring 2015 en
dc.relation.project info:eu-repo/grantAgreement/SFI/SFI Principal Investigator Programme (PI)/09/IN.1/I2633/IE/Investigating Emerging Non-Silicon Transistors (INVENT)/
dc.relation.project info:eu-repo/grantAgreement/SFI/SFI Strategic Research Cluster/07/SRC/I1172/IE/SRC FORME: Functional Oxides and Related Materials for Electronics/

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© 2014, Éamon O'Connor. Except where otherwise noted, this item's license is described as © 2014, Éamon O'Connor.
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