The Devices - Jan M. Rabaey ( Các thiết bị - tác giả Jan M.Rabaey )

• Present intuitive understanding of device operation • Introduction of basic device equations • Introduction of models for manual analysis • Introduction of models for SPICE simulation • Analysis of secondary and deep-sub-micron effects • Future trends

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The Devices Jan M. Rabaey Digital Integrated Circuits Introduction © Prentice Hall 1995 Goal of this chapter • Present intuitive understanding of device operation • Introduction of basic device equations • Introduction of models for manual analysis • Introduction of models for SPICE simulation • Analysis of secondary and deep-sub-micron effects • Future trends Digital Integrated Circuits Introduction © Prentice Hall 1995 The Diode B Al A SiO2 p n Cross-section of pn -junction in an IC process A Al p A n B B One-dimensional representation diode symbol Digital Integrated Circuits Introduction © Prentice Hall 1995 Depletion Region hole diffusion electron diffusion (a) Current flow. p n hole drift electron drift Charge ρ Density + x (b) Charge density. Distance - Electrical ξ Field x (c) Electric field. V Potential ψ0 (d) Electrostatic x potential. -W 1 W2 Digital Integrated Circuits Introduction © Prentice Hall 1995 Diode Current Digital Integrated Circuits Introduction © Prentice Hall 1995 Models for Manual Analysis ID = IS(eV D/φT – 1) ID + + + VD VD VDon – – – (a) Ideal diode model (b) First-order diode model Digital Integrated Circuits Introduction © Prentice Hall 1995 Junction Capacitance Digital Integrated Circuits Introduction © Prentice Hall 1995 Diode Switching Time Rsrc VD V1 ID Vsrc V2 t=0 t=T Excess charge Space charge VD ON OFF ON Time Digital Integrated Circuits Introduction © Prentice Hall 1995 Secondary Effects ID (A) 0.1 0 –0.1 –25.0 –15.0 –5.0 0 5.0 VD (V) Avalanche Breakdown Digital Integrated Circuits Introduction © Prentice Hall 1995 Diode Model RS + VD ID CD - Digital Integrated Circuits Introduction © Prentice Hall 1995 SPICE Parameters Digital Integrated Circuits Introduction © Prentice Hall 1995 The MOS Transistor Gate Oxyde Gate Polysilicon Field-Oxyde Source Drain (SiO2) n+ n+ p+ stopper p-substrate Bulk Contact CROSS-SECTION of NMOS Transistor Digital Integrated Circuits Introduction © Prentice Hall 1995 Cross-Section of CMOS Technology Digital Integrated Circuits Introduction © Prentice Hall 1995 MOS transistors Types and Symbols D D G G S S NMOS Enhancement NMOS Depletion D D G G B S S PMOS Enhancement NMOS with Bulk Contact Digital Integrated Circuits Introduction © Prentice Hall 1995 Transistor: No Voltages Gate Oxyde Gate Polysilicon Field-Oxyde Source Drain (SiO2) n+ n+ p+ stopper p-substrate Bulk Contact CROSS-SECTION of NMOS Transistor Digital Integrated Circuits Introduction © Prentice Hall 1995 Transistor “Off” Vgs Threshold Voltage: Concept + S VGS D G - n+ n+ n-channel Depletion Region p-substrate B Digital Integrated Circuits Introduction © Prentice Hall 1995 The Threshold Voltage Body Effect Out A ? B GND Digital Integrated Circuits Introduction © Prentice Hall 1995 Channel Formation Vgs>Vt + S VGS D G - Ids Vgd n+ n+ n-channel Depletion R Region Vgs p-substrate B I=V/R Ids Positive Charge on Gate: Channel exists, but no current since Vds = 0 Vds Introduction to VLSI Design Introduction © Steven P. Levitan 1998 Current-Voltage Relations VGS VDS S G ID D n+ – V(x) + n+ L x p-substrate B MOS transistor and its bias conditions Digital Integrated Circuits Introduction © Prentice Hall 1995