Threshold voltage

About: Threshold voltage is a research topic. Over the lifetime, 36543 publications have been published within this topic receiving 485574 citations.

Design of ion-implanted MOSFET's with very small physical dimensions

Abstract: This paper considers the design, fabrication, and characterization of very small Mosfet switching devices suitable for digital integrated circuits, using dimensions of the order of 1 /spl mu/. Scaling relationships are presented which show how a conventional MOSFET can be reduced in size. An improved small device structure is presented that uses ion implantation, to provide shallow source and drain regions and a nonuniform substrate doping profile. One-dimensional models are used to predict the substrate doping profile and the corresponding threshold voltage versus source voltage characteristic. A two-dimensional current transport model is used to predict the relative degree of short-channel effects for different device parameter combinations. Polysilicon-gate MOSFET's with channel lengths as short as 0.5 /spl mu/ were fabricated, and the device characteristics measured and compared with predicted values. The performance improvement expected from using these very small devices in highly miniaturized integrated circuits is projected.

Leakage current mechanisms and leakage reduction techniques in deep-submicrometer CMOS circuits

Abstract: High leakage current in deep-submicrometer regimes is becoming a significant contributor to power dissipation of CMOS circuits as threshold voltage, channel length, and gate oxide thickness are reduced. Consequently, the identification and modeling of different leakage components is very important for estimation and reduction of leakage power, especially for low-power applications. This paper reviews various transistor intrinsic leakage mechanisms, including weak inversion, drain-induced barrier lowering, gate-induced drain leakage, and gate oxide tunneling. Channel engineering techniques including retrograde well and halo doping are explained as means to manage short-channel effects for continuous scaling of CMOS devices. Finally, the paper explores different circuit techniques to reduce the leakage power consumption.

FinFET-a self-aligned double-gate MOSFET scalable to 20 nm

Abstract: MOSFETs with gate length down to 17 nm are reported To suppress the short channel effect, a novel self-aligned double-gate MOSFET, FinFET, is proposed By using boron-doped Si/sub 04/Ge/sub 06/ as a gate material, the desired threshold voltage was achieved for the ultrathin body device The quasiplanar nature of this new variant of the vertical double-gate MOSFETs can be fabricated relatively easily using the conventional planar MOSFET process technologies

Silicon-on-Insulator Technology: Materials to VLSI

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.- 2.2.2.1 Silicon-on-Zirconia (SOZ).- 2.2.2.2 Silicon-on-Spinel.- 2.2.2.3 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).- 2.7.1.1 "Standard"SIMOX.- 2.7.1.2 Low-dose SIMOX.- 2.7.1.3 ITOX.- 2.7.1.4 SMOXMLD.- 2.7.1.5 Related techniques.- 2.7.1.6 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).- 2.9.1.1 Hydrogen / rare gas implantation.- 2.9.1.2 Bonding to a stiffener.- 2.9.1.3 Annealing.- 2.9.1.4 Splitting.- 2.9.1.5 Further developments.- 2.9.2 Eltran(R).- 2.9.2.1 Porous silicon formation.- 2.9.2.2 The original Eltran(R) process.- 2.9.2.3 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.- 3.3.3.1 Most common defects.- 3.3.3.2 Chemical decoration of defects.- 3.3.3.3 Detection of defects by light scattering.- 3.3.3.4 Other defect assessment techniques.- 3.3.3.5 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.- 3.4.3.1 Accumulation-mode transistor.- 3.4.3.2 Inversion-mode transistor.- 3.4.3.3 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.- 6.1.1.1 Double-gate SOI MOSFETs.- 6.1.1.2 Triple-gate SOI MOSFETs.- 6.1.1.3 Surrounding-gate SOI MOSFETs.- 6.1.1.4 Triple-plus gate SOI MOSFETs..- 6.1.2 Device characteristics.- 6.1.2.1 Current drive.- 6.1.2.2 Short-channel effects.- 6.1.2.3 Threshold voltage.- 6.1.2.4 Volume inversion.- 6.1.2.5 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.- 8.2.3.1 Non volatile memory devices.- 8.2.3.2 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.

Wide-bandgap high-mobility ZnO thin-film transistors produced at room temperature

Abstract: We report high-performance ZnO thin-film transistor (ZnO-TFT) fabricated by rf magnetron sputtering at room temperature with a bottom gate configuration. The ZnO-TFT operates in the enhancement mode with a threshold voltage of 19V, a saturation mobility of 27cm2∕Vs, a gate voltage swing of 1.39V∕decade and an on/off ratio of 3×105. The ZnO-TFT presents an average optical transmission (including the glass substrate) of 80% in the visible part of the spectrum. The combination of transparency, high mobility, and room-temperature processing makes the ZnO-TFT a very promising low-cost optoelectronic device for the next generation of invisible and flexible electronics.