The Experts below are selected from a list of 73137 Experts worldwide ranked by ideXlab platform
Yoshio Nishi - One of the best experts on this subject based on the ideXlab platform.
-
contact engineering for organic semiconductor devices via Fermi Level depinning at the metal organic interface
Physical Review B, 2010Co-Authors: Masaharu Kobayashi, Bipul C Paul, Yoshio NishiAbstract:Organic or carbon semiconductor devices are promising for both nanoelectronic and macroelectronic applications. One of the major challenges to achieve high performance of these devices lies on understanding and improving the metal-organic (M/O) interface. In this paper, we present evidence and demonstration of Fermi-Level depinning at the M/O interface by inserting an ultrathin interfacial ${\text{Si}}_{3}{\text{N}}_{4}$ insulator in between. The M/O contact behavior is successfully tuned from rectifying to quasi-Ohmic and to tunneling by varying the ${\text{Si}}_{3}{\text{N}}_{4}$ thickness within 0\char21{}6 nm. Detailed physical mechanisms of Fermi-Level pinning/depinning responsible for the M/O contact behavior are clarified based on a lumped-dipole model and a simple depinning model. This work sheds light on the fundamental understanding of the M/O interface properties and also proves a practical engineering method of achieving low-resistance quasi-Ohmic contacts for organic electronic devices.
-
Fermi Level depinning at metal organic semiconductor interface for low resistance ohmic contacts
International Electron Devices Meeting, 2009Co-Authors: Zihong Liu, Masaharu Kobayashi, Bipul C Paul, Zhenan Bao, Yoshio NishiAbstract:This paper presents the direct evidence and successful demonstration of Fermi-Level depinning at metal-organic semiconductor (M/O) interfaces by inserting an ultrathin interfacial Si 3 N 4 insulator in between. The contact behavior is tuned from rectifying to quasi-Ohmic and to tunneling by varying the Si 3 N 4 thickness within 0–6 nm. Detailed physical mechanisms of Fermi-Level pinning/depinning responsible for the M/O contact behavior are clarified based on a proposed lumped-dipole model. Experimental results are in good agreement with the theory and model. This work represents a significant step toward the fundamental understanding of M/O interface properties and technological advancement of achieving low-resistance Ohmic contacts for organic electronic device (e.g. thin-film transistor) applications.
-
Fermi Level depinning in metal ge schottky junction for metal source drain ge metal oxide semiconductor field effect transistor application
Journal of Applied Physics, 2009Co-Authors: Masaharu Kobayashi, Atsuhiro Kinoshita, K C Saraswat, H Philip S Wong, Yoshio NishiAbstract:Schottky barrier height modulation in metal/Ge Schottky junction was demonstrated by inserting an ultrathin interfacial silicon nitride layer. The SiN interfacial layer suppressed strong Fermi Level pinning in metal/Ge Schottky junction, which resulted in effective control of Schottky barrier height. Metal/SiN/Ge Schottky diode was systematically investigated in terms of SiN thickness dependence and metal work function dependence. At an optimal SiN thickness, Ohmic contact between metal and Ge was obtained as a result of Fermi Level depinning, and almost ideal Schottky barrier height determined by the work function difference between the metal and Ge was achieved. This technology was finally applied to metal source/drain Ge metal-oxide-semiconductor field-effect-transistors with low source/drain resistance.
-
Fermi Level depinning in metal ge schottky junction and its application to metal source drain ge nmosfet
Symposium on VLSI Technology, 2008Co-Authors: Masaharu Kobayashi, Atsuhiro Kinoshita, K C Saraswat, H S P Wong, Yoshio NishiAbstract:We successfully demonstrated Schottky barrier height modulation in metal/Ge Schottky junction by inserting an ultrathin interfacial SiN layer. The SiN layer suppressed strong Fermi Level pinning in metal/Ge junction, which resulted in effective control of the Schottky barrier height. We systematically investigated its physics, for the first time, and almost zero Schottky barrier height was successfully obtained for electrons. We applied this technology to metal source/drain Ge NMOSFET and achieved low source/drain resistance.
Masaharu Kobayashi - One of the best experts on this subject based on the ideXlab platform.
-
contact engineering for organic semiconductor devices via Fermi Level depinning at the metal organic interface
Physical Review B, 2010Co-Authors: Masaharu Kobayashi, Bipul C Paul, Yoshio NishiAbstract:Organic or carbon semiconductor devices are promising for both nanoelectronic and macroelectronic applications. One of the major challenges to achieve high performance of these devices lies on understanding and improving the metal-organic (M/O) interface. In this paper, we present evidence and demonstration of Fermi-Level depinning at the M/O interface by inserting an ultrathin interfacial ${\text{Si}}_{3}{\text{N}}_{4}$ insulator in between. The M/O contact behavior is successfully tuned from rectifying to quasi-Ohmic and to tunneling by varying the ${\text{Si}}_{3}{\text{N}}_{4}$ thickness within 0\char21{}6 nm. Detailed physical mechanisms of Fermi-Level pinning/depinning responsible for the M/O contact behavior are clarified based on a lumped-dipole model and a simple depinning model. This work sheds light on the fundamental understanding of the M/O interface properties and also proves a practical engineering method of achieving low-resistance quasi-Ohmic contacts for organic electronic devices.
-
Fermi Level depinning at metal organic semiconductor interface for low resistance ohmic contacts
International Electron Devices Meeting, 2009Co-Authors: Zihong Liu, Masaharu Kobayashi, Bipul C Paul, Zhenan Bao, Yoshio NishiAbstract:This paper presents the direct evidence and successful demonstration of Fermi-Level depinning at metal-organic semiconductor (M/O) interfaces by inserting an ultrathin interfacial Si 3 N 4 insulator in between. The contact behavior is tuned from rectifying to quasi-Ohmic and to tunneling by varying the Si 3 N 4 thickness within 0–6 nm. Detailed physical mechanisms of Fermi-Level pinning/depinning responsible for the M/O contact behavior are clarified based on a proposed lumped-dipole model. Experimental results are in good agreement with the theory and model. This work represents a significant step toward the fundamental understanding of M/O interface properties and technological advancement of achieving low-resistance Ohmic contacts for organic electronic device (e.g. thin-film transistor) applications.
-
Fermi Level depinning in metal ge schottky junction for metal source drain ge metal oxide semiconductor field effect transistor application
Journal of Applied Physics, 2009Co-Authors: Masaharu Kobayashi, Atsuhiro Kinoshita, K C Saraswat, H Philip S Wong, Yoshio NishiAbstract:Schottky barrier height modulation in metal/Ge Schottky junction was demonstrated by inserting an ultrathin interfacial silicon nitride layer. The SiN interfacial layer suppressed strong Fermi Level pinning in metal/Ge Schottky junction, which resulted in effective control of Schottky barrier height. Metal/SiN/Ge Schottky diode was systematically investigated in terms of SiN thickness dependence and metal work function dependence. At an optimal SiN thickness, Ohmic contact between metal and Ge was obtained as a result of Fermi Level depinning, and almost ideal Schottky barrier height determined by the work function difference between the metal and Ge was achieved. This technology was finally applied to metal source/drain Ge metal-oxide-semiconductor field-effect-transistors with low source/drain resistance.
-
Fermi Level depinning in metal ge schottky junction and its application to metal source drain ge nmosfet
Symposium on VLSI Technology, 2008Co-Authors: Masaharu Kobayashi, Atsuhiro Kinoshita, K C Saraswat, H S P Wong, Yoshio NishiAbstract:We successfully demonstrated Schottky barrier height modulation in metal/Ge Schottky junction by inserting an ultrathin interfacial SiN layer. The SiN layer suppressed strong Fermi Level pinning in metal/Ge junction, which resulted in effective control of the Schottky barrier height. We systematically investigated its physics, for the first time, and almost zero Schottky barrier height was successfully obtained for electrons. We applied this technology to metal source/drain Ge NMOSFET and achieved low source/drain resistance.
Akira Toriumi - One of the best experts on this subject based on the ideXlab platform.
-
potential influence of surface atomic disorder on Fermi Level pinning at metal sige interface
IEEE Electron Devices Technology and Manufacturing Conference, 2018Co-Authors: Xuan Luo, Takeaki Yajima, T Nishimura, Akira ToriumiAbstract:The Schottky barrier heights (SBH) at metal/n-Si 0.55 Ge 0.45 Schottky interface are reported as a function of work function of metals. In comparison of the pinning strength with metal/Si and metal/Ge, the result shows that a large amount of disorders and defects on SiGe do not have a significant effect on the Fermi Level pinning (FLP), which may suggest that the intrinsic instead of extrinsic mechanism should be considered for the dominant mechanism of Fermi Level pinning not only at metal/SiGe but also at metal/Si and Ge systems.
-
reexamination of Fermi Level pinning for controlling schottky barrier height at metal ge interface
Applied Physics Express, 2016Co-Authors: Tomonori Nishimura, Takeaki Yajima, Akira ToriumiAbstract:The element metal/germanium (Ge) interface exhibits a strong Fermi Level pinning (FLP), which is usually characterized on the basis of Ge side semiconductor properties. In this work, we demonstrate that metal properties significantly affect the Schottky barrier height (SBH) on Ge. Metallic germanides show both FLP alleviation and a clear substrate orientation dependence of SBH on Ge, despite the nearly perfect FLP and very slight orientation dependence in the element metal case. As a result, ohmic characteristics are observed at germanide/n-Ge (111) junctions. The metal properties required to alleviate the FLP on Ge are also discussed.
-
evidence for strong Fermi Level pinning due to metal induced gap states at metal germanium interface
Applied Physics Letters, 2007Co-Authors: Tomonori Nishimura, Koji Kita, Akira ToriumiAbstract:The purpose of this paper is to understand metal/germanium (Ge) junction characteristics. Electrode metals with a wide work function range were deposited on Ge. All metal/p-Ge and metal/n-Ge junctions have shown Ohmic and Schottky characteristics, respectively, with the strong Fermi-Level pinning. The charge neutrality Level (CNL) at metal/Ge interface is close to the branch point calculated for the bulk Ge. Moreover, the pinning Level is hardly modulated by annealing in forming gas, forming metal-germanide/Ge interfaces or changing the substrate orientation. These results suggest that Fermi Level at metal/Ge interface is intrinsically pinned at the CNL characterized by the metal-induced gap states model.
Seiji Mita - One of the best experts on this subject based on the ideXlab platform.
-
defect quasi Fermi Level control based cn reduction in gan evidence for the role of minority carriers
Applied Physics Letters, 2017Co-Authors: Pramod Reddy, Felix Kaess, James Tweedie, Ronny Kirste, Seiji Mita, Ramon Collazo, Zlatko SitarAbstract:Compensating point defect reduction in wide bandgap semiconductors is possible by above bandgap illumination based defect quasi Fermi Level (dQFL) control. The point defect control technique employs excess minority carriers that influence the dQFL of the compensator, increase the corresponding defect formation energy, and consequently are responsible for point defect reduction. Previous studies on various defects in GaN and AlGaN have shown good agreement with the theoretical model, but no direct evidence for the role of minority carriers was provided. In this work, we provide direct evidence for the role of minority carriers in reducing point defects by studying the predicted increase in work done against defect (CN−1) formation with the decrease in the Fermi Level (free carrier concentration) in Si doped GaN at a constant illumination intensity. Comparative defect photoluminescence measurements on illuminated and dark regions of GaN show an excellent quantitative agreement with the theory by exhibiting ...
-
point defect reduction in wide bandgap semiconductors by defect quasi Fermi Level control
Journal of Applied Physics, 2016Co-Authors: Pramod Reddy, Felix Kaess, James Tweedie, Ronny Kirste, Marc P Hoffmann, Zachary Bryan, Isaac Bryan, Milena Bobea, Andrew Klump, Seiji MitaAbstract:A theoretical framework for a general approach to reduce point defect density in materials via control of defect quasi Fermi Level (dQFL) is presented. The control of dQFL is achieved via excess minority carrier generation. General guidelines for controlling dQFL that lead to a significant reduction in compensating point defects in any doped material is proposed. The framework introduces and incorporates the effects of various factors that control the efficacy of the defect reduction process such as defect Level, defect formation energy, bandgap, and excess minority carrier density. Modified formation energy diagrams are proposed, which illustrate the effect of the quasi Fermi Level control on the defect formation energies. These formation energy diagrams provide powerful tools to determine the feasibility and requirements to produce the desired reduction in specified point defects. An experimental study of the effect of excess minority carriers on point defect incorporation in GaN and AlGaN shows an exce...
-
strain in si doped gan and the Fermi Level effect
Applied Physics Letters, 2011Co-Authors: Jinqiao Xie, James Tweedie, Seiji Mita, Ramon Collazo, Anthony Rice, Lindsay Hussey, Zlatko SitarAbstract:Using high resolution x-ray diffraction and Hall effect measurements, we found that the tensile strain caused by dislocation inclination in Si doped GaN became immeasurable when carbon codoping was used to compensate the free carriers. This result suggested that the tensile strain is related to free carrier concentration instead of Si concentration. Such an effect could be explained by the Fermi Level effect on the surface-mediated dislocation climb governed by Ga vacancies, whose concentration is strongly influenced by the Fermi Level position. This phenomenon is possibly similar to the well-known Fermi Level effect in GaAs and GaP systems.
K C Saraswat - One of the best experts on this subject based on the ideXlab platform.
-
analysis of atomistic dopant variation and Fermi Level depinning in nanoscale contacts
IEEE Transactions on Electron Devices, 2017Co-Authors: Gautam Shine, K C SaraswatAbstract:Using quantum transport simulations of metal–semiconductor junctions, we assess the viability of barrier thinning with dopants and barrier lowering with interfacial layers as solutions for contact resistivity in nanoscale transistors. Our atomistic simulations show that the discreteness of dopants leads to increasing variability in contact resistance as dimensions scale below 10 nm. We find that the use of interlayers can counteract low doping caused by atomistic variation, but the interlayer must have band edge Fermi Level pinning to provide a net reduction in contact resistivity. For materials with low doping limits, such as n-type germanium, we find that interlayer contacts still have difficulty meeting resistivity targets.
-
Fermi Level depinning in metal ge schottky junction for metal source drain ge metal oxide semiconductor field effect transistor application
Journal of Applied Physics, 2009Co-Authors: Masaharu Kobayashi, Atsuhiro Kinoshita, K C Saraswat, H Philip S Wong, Yoshio NishiAbstract:Schottky barrier height modulation in metal/Ge Schottky junction was demonstrated by inserting an ultrathin interfacial silicon nitride layer. The SiN interfacial layer suppressed strong Fermi Level pinning in metal/Ge Schottky junction, which resulted in effective control of Schottky barrier height. Metal/SiN/Ge Schottky diode was systematically investigated in terms of SiN thickness dependence and metal work function dependence. At an optimal SiN thickness, Ohmic contact between metal and Ge was obtained as a result of Fermi Level depinning, and almost ideal Schottky barrier height determined by the work function difference between the metal and Ge was achieved. This technology was finally applied to metal source/drain Ge metal-oxide-semiconductor field-effect-transistors with low source/drain resistance.
-
Fermi Level depinning in metal ge schottky junction and its application to metal source drain ge nmosfet
Symposium on VLSI Technology, 2008Co-Authors: Masaharu Kobayashi, Atsuhiro Kinoshita, K C Saraswat, H S P Wong, Yoshio NishiAbstract:We successfully demonstrated Schottky barrier height modulation in metal/Ge Schottky junction by inserting an ultrathin interfacial SiN layer. The SiN layer suppressed strong Fermi Level pinning in metal/Ge junction, which resulted in effective control of the Schottky barrier height. We systematically investigated its physics, for the first time, and almost zero Schottky barrier height was successfully obtained for electrons. We applied this technology to metal source/drain Ge NMOSFET and achieved low source/drain resistance.