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Subthreshold slope

About: Subthreshold slope is a(n) research topic. Over the lifetime, 3014 publication(s) have been published within this topic receiving 70424 citation(s).
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Journal ArticleDOI
Jean-Pierre Colinge1, Chi-Woo Lee1, Aryan Afzalian2, Aryan Afzalian1  +10 moreInstitutions (2)
TL;DR: A new type of transistor in which there are no junctions and no doping concentration gradients is proposed and demonstrated, which has near-ideal subthreshold slope, extremely low leakage currents, and less degradation of mobility with gate voltage and temperature than classical transistors.
Abstract: All existing transistors are based on the use of semiconductor junctions formed by introducing dopant atoms into the semiconductor material. As the distance between junctions in modern devices drops below 10 nm, extraordinarily high doping concentration gradients become necessary. Because of the laws of diffusion and the statistical nature of the distribution of the doping atoms, such junctions represent an increasingly difficult challenge for the semiconductor industry. Here, we propose and demonstrate a new type of transistor in which there are no junctions and no doping concentration gradients. These devices have full CMOS functionality and are made using silicon nanowires. They have near-ideal subthreshold slope, extremely low leakage currents, and less degradation of mobility with gate voltage and temperature than classical transistors.

1,859 citations

31 Mar 1991-
Abstract: 1 Introduction.- 2 SOI Materials.- 2.1 Introduction.- 2.2 Heteroepitaxial techniques.- 2.2.1 Silicon-on-Sapphire (SOS).- 2.2.2 Other heteroepitaxial SOI materials.- Silicon-on-Zirconia (SOZ).- Silicon-on-Spinel.- Silicon on Calcium Fluoride.- 2.3 Dielectric Isolation (DI).- 2.4 Polysilicon melting and recrystallization.- 2.4.1 Laser recrystallization.- 2.4.2 E-beam recrystallization.- 2.4.3 Zone-melting recrystallization.- 2.5 Homoepitaxial techniques.- 2.5.1 Epitaxial lateral overgrowth.- 2.5.2 Lateral solid-phase epitaxy.- 2.6 FIPOS.- 2.7 Ion beam synthesis of a buried insulator.- 2.7.1 Separation by implanted oxygen (SIMOX).- "Standard"SIMOX.- Low-dose SIMOX.- ITOX.- SMOXMLD.- Related techniques.- Material quality.- 2.7.2 Separation by implanted nitrogen (SIMNI).- 2.7.3 Separation by implanted oxygen and nitrogen (SIMON).- 2.7.4 Separation by implanted Carbon.- 2.8 Wafer Bonding and Etch Back (BESOI).- 2.8.1 Hydrophilic wafer bonding.- 2.8.2 Etch back.- 2.9 Layer transfer techniques.- 2.9.1 Smart-Cut(R).- Hydrogen / rare gas implantation.- Bonding to a stiffener.- Annealing.- Splitting.- Further developments.- 2.9.2 Eltran(R).- Porous silicon formation.- The original Eltran(R) process.- Second-generation Eltran(R) process.- 2.9.3 Transferred layer material quality.- 2.10 Strained silicon on insulator (SSOI).- 2.11 Silicon on diamond.- 2.12 Silicon-on-nothing (SON).- 3 SOI Materials Characterization.- 3.1 Introduction.- 3.2 Film thickness measurement.- 3.2.1 Spectroscopic reflectometry.- 3.2.2 Spectroscopic ellipsometry.- 3.2.3 Electrical thickness measurement.- 3.3 Crystal quality.- 3.3.1 Crystal orientation.- 3.3.2 Degree of crystallinity.- 3.3.3 Defects in the silicon film.- Most common defects.- Chemical decoration of defects.- Detection of defects by light scattering.- Other defect assessment techniques.- Stress in the silicon film.- 3.3.4 Defects in the buried oxide.- 3.3.5 Bond quality and bonding energy.- 3.4 Carrier lifetime.- 3.4.1 Surface Photovoltage.- 3.4.2 Photoluminescence.- 3.4.3 Measurements on MOS transistors.- Accumulation-mode transistor.- Inversion-mode transistor.- Bipolar effect.- 3.5 Silicon/Insulator interfaces.- 3.5.1 Capacitance measurements.- 3.5.2 Charge pumping.- 3.5.3 ?-MOSFET.- 4 SOI CMOS Technology.- 4.1 SOI CMOS processing.- 4.1.1 Fabrication yield and fabrication cost.- 4.2 Field isolation.- 4.2.1 LOCOS.- 4.2.2 Mesa isolation.- 4.2.3 Shallow trench isolation.- 4.2.4 Narrow-channel effects.- 4.3 Channel doping profile.- 4.4 Source and drain engineering.- 4.4.1 Silicide source and drain.- 4.4.2 Elevated source and drain.- 4.4.3 Tungsten clad.- 4.4.4 Schottky source and drain.- 4.5 Gate stack.- 4.5.1 Gate material.- 4.5.2 Gate dielectric.- 4.5.3 Gate etch.- 4.6 SOI MOSFET layout.- 4.6.1 Body contact.- 4.7 SOI-bulk CMOS design comparison.- 4.8 ESD protection.- 5 The SOI MOSFET.- 5.1 Capacitances.- 5.1.1 Source and drain capacitance.- 5.1.2 Gate capacitance.- 5.2 Fully and partially depleted devices.- 5.3 Threshold voltage.- 5.3.1 Body effect.- 5.3.2 Short-channel effects.- 5.4 Current-voltage characteristics.- 5.4.1 Lim & Fossum model.- 5.4.2 C?-continuous model.- 5.5 Transconductance.- 5.5.1 gm/ID ratio.- 5.5.2 Mobility.- 5.6 Basic parameter extraction.- 5.6.1 Threshold voltage and mobility.- 5.6.2 Source and drain resistance.- 5.7 Subthreshold slope.- 5.8 Ultra-thin SOI MOSFETs.- 5.8.1 Threshold voltage.- 5.8.2 Mobility.- 5.9 Impact ionization and high-field effects.- 5.9.1 Kink effect.- 5.9.2 Hot-carrier degradation.- 5.10 Floating-body and parasitic BJT effects.- 5.10.1 Anomalous subthreshold slope.- 5.10.2 Reduced drain breakdown voltage.- 5.10.3 Other floating-body effects.- 5.11 Self heating.- 5.12 Accumulation-mode MOSFET.- 5.12.1 I-V characteristics.- 5.12.2 Subthreshold slope.- 5.13 Unified body-effect representation.- 5.14 RF MOSFETs.- 5.15 CAD models for SOI MOSFETs.- 6 Other SOI Devices.- 6.1 Multiple-gate SOI MOSFETs.- 6.1.1 Multiple-gate SOI MOSFET structures.- Double-gate SOI MOSFETs.- Triple-gate SOI MOSFETs.- Surrounding-gate SOI MOSFETs.- Triple-plus gate SOI MOSFETs..- 6.1.2 Device characteristics.- Current drive.- Short-channel effects.- Threshold voltage.- Volume inversion.- Mobility.- 6.2 MTCMOS/DTMOS.- 6.3 High-voltage devices.- 6.3.1 VDMOS and LDMOS.- 6.3.2 Other high-voltage devices.- 6.4 Junction Field-Effect Transistor.- 6.5 Lubistor.- 6.6 Bipolar junction transistors.- 6.7 Photodiodes.- 6.8 G4 FET.- 6.9 Quantum-effect devices.- 7 The SOI MOSFET in a Harsh Environment.- 7.1 Ionizing radiations.- 7.1.1 Single-event phenomena.- 7.1.2 Total dose effects.- 7.1.3 Dose-rate effects.- 7.2 High-temperature operation.- 7.2.1 Leakage current.- 7.2.2 Threshold voltage.- 7.2.3 Output conductance.- 7.2.4 Subthreshold slope.- 8 SOI Circuits.- 8.1 Introduction.- 8.2 Mainstream CMOS applications.- 8.2.1 Digital circuits.- 8.2.2 Low-voltage, low-power digital circuits.- 8.2.3 Memory circuits.- Non volatile memory devices.- Capacitorless DRAM.- 8.2.4 Analog circuits.- 8.2.5 Mixed-mode circuits.- 8.3 Niche applications.- 8.3.1 High-temperature circuits.- 8.3.2 Radiation-hardened circuits.- 8.3.3 Smart-power circuits.- 8.4 Three-dimensional integration.

1,581 citations

Journal ArticleDOI
Kathy Boucart, Adrian M. Ionescu1Institutions (1)
Abstract: In this paper, we propose and validate a novel design for a double-gate tunnel field-effect transistor (DG tunnel FET), for which the simulations show significant improvements compared with single-gate devices using a gate dielectric. For the first time, DG tunnel FET devices, which are using a high-gate dielectric, are explored using realistic design parameters, showing an on-current as high as 0.23 mA for a gate voltage of 1.8 V, an off-current of less than 1 fA (neglecting gate leakage), an improved average subthreshold swing of 57 mV/dec, and a minimum point slope of 11 mV/dec. The 2D nature of tunnel FET current flow is studied, demonstrating that the current is not confined to a channel at the gate-dielectric surface. When varying temperature, tunnel FETs with a high-kappa gate dielectric have a smaller threshold voltage shift than those using SiO2, while the subthreshold slope for fixed values of Vg remains nearly unchanged, in contrast with the traditional MOSFET. Moreover, an Ion/Ioff ratio of more than 2 times 1011 is shown for simulated devices with a gate length (over the intrinsic region) of 50 nm, which indicates that the tunnel FET is a promising candidate to achieve better-than-ITRS low-standby-power switch performance.

1,061 citations

Journal ArticleDOI
Dong-un Jin1, Jae-Sup Lee1, Tae-Woong Kim1, Sung-Guk An1  +7 moreInstitutions (1)
01 Jun 2009-
Abstract: The world largest flexible full color 6.5-inch active matrix organic light emitting diode (AMOLED) display with top emission mode on plastic film is demonstrated. The active matrix backplanes were fabricated using metal oxide thin film transistors (TFTs). The n-channel metal oxide TFTs on plastic film exhibited field-effect mobility of 17.8 cm2/Vs, threshold voltage of 0.4 V, on/off ratio of 1.1× 108, and subthreshold slope of 0.34 V/dec. These TFT performance characteristics made it possible to integrate scan driver circuit, demux switching and compensation circuit on the panel. Bending tests were performed with TFT backplane samples to determine critical curvature radius to which the panel can be bent without TFT performance degradation. The results were compared with the calculations that took into account thicknesses and mechanical constants of flexible substrate and of thin-film layers in AMOLED device.

994 citations

Journal ArticleDOI
Abstract: Using two layers of pentacene deposited at different substrate temperatures as the active material, we have fabricated photolithographically defined organic thin-film transistors (OTFTs) with improved field-effect mobility and subthreshold slope. These devices use photolithographically defined gold source and drain electrodes and octadecyltrichlorosilane-treated silicon dioxide gate dielectric. The devices have field-effect mobility as large as 1.5 cm/sup 2//V-s, on/off current ratio larger than 10/sup 8/, near zero threshold voltage, and subthreshold slope less than 1.6 V per decade. To our knowledge, this is the largest field-effect mobility and smallest subthreshold slope yet reported for any organic transistor, and the first time both of these important characteristics have been obtained for a single device.

901 citations

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