当前位置:首页 >> 电子/电路 >>

TCAD Sentaurus introduction 2014


Sentaurus TCAD Introduction

Franck Nallet
Paris - 15/09/2014

? Synopsys 2013

1

CONFIDENTIAL INFORMATION
The following material is being disclosed to you pursuant to a non-disclosure agreement between you or your employer and Synopsys. Information disclosed in this presentation may be used only as permitted under such an agreement.

LEGAL NOTICE
Information contained in this presentation reflects Synopsys plans as of the date of this presentation. Such plans are subject to completion and are subject to change. Products may be offered and purchased only pursuant to an authorized quote and purchase order. Synopsys is not obligated to develop the software with the features and functionality discussed in the materials.

? Synopsys 2013

2

TCAD Application Segments
CMOS
? ? ? ? Advanced CMOS (Si, SOI, etc.) Atomistic modeling Statistical modeling Reliability

Analog/RF
? High-speed devices ? Compound semiconductors

Memory

? Flash ? DRAM ? ReRAM

Power

? ? ? ?

Discrete devices Power ICs Silicon and wide bandgap ESD

Opto

? Image Sensors ? Solar Cells ? Photodetectors

? Synopsys 2013

3

TCAD Product Portfolio
Sentaurus Lithography
Sentaurus Process Sentaurus Topography

Sentaurus Process

Framework
Sentaurus Workbench

Process Simulation
Sentaurus Structure Editor

Sentaurus Lithography Sentaurus Topography

Structure Editing

Sentaurus Workbench Sentaurus Structure Editor

Sentaurus Device

Device and Interconnect Simulation

Raphael Sentaurus Interconnect

Sentaurus PCM Studio
Sentaurus PCM Studio

Sentaurus Device Raphael Sentaurus Interconnect

? Synopsys 2013

4

TCAD Development Focuses
? New Technology Support
– More Moore
– – FinFET, FDSOI, III-V, etc. Analog/RF, CIS, solar, power (Si, SiC, GaN), TSV, etc.

– More than Moore

? 3D Support (FinFET, NVM, Power, SRAM, CIS)
– Improved meshing and geometric operations – Stress modeling – BEOL reliability modeling – Topography simulation

? Performance and Usability
– Improved multi-CPU scaling
– Process simulation speed-up – More intuitive user interface
? Synopsys 2013 5

TCAD Supported Platforms
Platforms supported in I-2013.12 release:
? x86_641 Red Hat Enterprise Linux 5.7, 5.9, 6.2, 6.4 ? x86_641 SUSE Linux Enterprise Server 10SP3, 10SP42, 11SP12, 11SP22 ? IBM RS6000 64-bit AIX3 6.1-TL6-SP5

1. The 64-bit (x86_64) Linux software is binary compatible with the Intel orAMDx86_64 processors running Red Hat Enterprise Linux. 2. Binary-compatible hardware platform or operating system. Note, however, that binary compatibility is not guaranteed. 3. Sentaurus Device Electromagnetic Wave Solver, Sentaurus Interconnect, Sentaurus Topography, and Sentaurus Topography 3D are not available on AIX.

? Synopsys 2013

6

Sentaurus Workbench – TCAD Simulation Platform
? Sentaurus Workbench GUI
Tools

Simulation Tree

Simulation Branch

Projects

Nodes
? Synopsys 2013 7

Sentaurus Workbench – Easy Material & Manual Access
Manuals HTMLtraining

Public Application Example Library

? Synopsys 2013

8

Sentaurus Workbench – Node Explorer
? Node Explorer (F7) provides quick access to all node data

mouse double-click on node

? Synopsys 2013

9

Sentaurus Workbench – Flexible Execution Controls

selected nodes run with one mouse click

? Synopsys 2013

10

Sentaurus Process Simulator
? General purpose multidimensional (2D/3D) process simulator ? Integrated 3D geometric modeling engine (depo/etch/pattern)

? Adaptive meshing (to geometry/species changes)
? API for user-defined models ? Advanced physical models:
– – – – Analytic and Monte Carlo implantation Diffusion: laser/flash annealing, kinetic Monte Carlo Mechanical stress Oxidation/Silicidation
FinFET SRAM

Mechanical Stress
? Synopsys 2013 11

Kinetic Monte Carlo

Adaptive Meshing

Oxidation

Implantation
implant Arsenic dose=1e14 energy=50 tilt=7 rotation=0 info=2

? MC Implantation
? Sentaurus MC ? (Crystal-TRIM)

? Analytic Implantation
? Primary Distributions
o Gaussian o Pearson (4 parameters) o Dual Pearson (9 parameters)

? ? ? ? ?

Screening Damage Model Amorphization Molecular Implant Calibrated Implantation Tables

? Synopsys 2013

12

Dopant Diffusion
? ? ? ? ? ? Flash/Laser Anneal Dopant Activation and Clustering Solid Phase Epitaxial Regrowth Epitaxy Clustering of Defects Pressure-dependent Defect Diffusion ? Segregation & Dose Loss ? Kinetic MC Diffusion
? Diffusion Model Hierarchy
? ? ? ? ? ? ? Constant (constant diffusion coefficient) Fermi (point defects equation not solved, defects in equilibrium) Charged Fermi (same as Fermi+total dopant flux is due to dopant-defect pairs) Pair (dopant-defects pairs are in local equilibrium with dopant and defect concentrations) Charged Pair (same as Pair+reaction rates are state charge dependent) React (incl.defects, rates are not charge state dependent) Charged React (same as React+mobile charged dopant-defects)
13

? Synopsys 2013

Oxidation/Silicidation
? Oxidation Model Hierarhy
? Deal/Grove Model ? Massoud Model ? Mixed Flows (Hirabayashi approach)

? ? ? ? ?

? ? ? ?

Stress-Dependent Oxidation (SDO) Orientation-Dependent Oxidation Doping-Dependent Oxidation Trap-Dependent Oxidation In Situ Steam-Generated Oxidation (ISSG) Silicidation Oxynitridation (N20) Moving Boundaries and Adaptive Mesh 3D Oxidation

? Synopsys 2013

14

Mechanical Stress Modeling
? Stress Model
? Viscoplasticity ? Plasticity ? Viscoelasticity

? Stress Causing Mechanisms
? ? ? ? ? Stress Induced by Growth of Material Stress Induced by Densification Stress Induced by Thermal Mismatch Lattice Mismatch Stress Intrinsic Stress

? Synopsys 2013

15

Etching/Deposition
? Etch Models
? ? ? ? ? ? ? ? ? ? ? Isotropic Anisotropic & Directional Polygonal CMP Fourier Crystallographic Trapezoidal Isotropic Fill & Polygon Fourier Selective Deposition

? Depo Models

? 3D Geometry Generation
? ? ? ? MGOALS3D (level-set) Integrated SDE S-Topo 3D Meshing with Sentaurus Mesh

? Algorithms
? Analytic ? Level-set

? Synopsys 2013

16

Non-Si Materials Process Simulation
? MC Implantation
? SiGe and Ge ? 4H-, 6H-SiC ? III-V, including III-N ? Diffusion & Activation ? First prototype available in H2013.03 release for 4H-SiC and III-V (InGaAs/InP)

? Synopsys 2013

17

Sentaurus Process Kinetic MC
? Command to switch
SetAtomistic

? Considers only defects and impurities, and ignores the lattice for diffusion simulation ? Supported options: diffuse, deposit, etch, implant, init, line, photo, profile, region, select, strip ? LKMC: Fully Atomistic Modeling of SPER (Solid Phase Epitaxial Regrowth)

? SPER velocity depends on the substrate orientation with approximate ratios of 20:10:1 for orientations (100), (110), and (111) (111) planes Oxide

amorphous Si

crystalline Si
? Synopsys 2013 18

Sentaurus Topography 3D
General overview
? Sentaurus Topography 3D is a three-dimensional simulator for evaluating and optimizing critical topography-processing steps such as etching and deposition ? Simulates deposition and etching processes by using the level-set method to evaluate the surface evolution during the process ? Models categories:
– Built-in models – User-defined models within Rate Formula Module (RFM) – User-defined models within a Physical Model Interface (PMI)

? Support of different reaction species, different fluxes, re-deposition, …
? Synopsys 2013 19

Sentaurus Topography Simulator
? ? ? ? ? Multidimensional (2D/3D) Robust level-set numerical models Deposition models (LPCVD, PECVD, HDP-CVD, APCVD, SOG, reflow) Etching models (wet, HDP, RIE, ion milling, CMP) Interface to Sentaurus Process & Sentaurus Lithography

Physical vapor deposition

Ion milling

RIE

O3 / TEOS APCVD
? Synopsys 2013 20

Tench filling with void formation

Etching and Deposition Example
DRAM Flow, using built-in models

1 3

5 2

4

? Synopsys 2013

21

Coupling Topography to Process

Geometry Sentaurus Topography
? Synopsys 2013 22

Doping and meshing Sentaurus Process

Sentaurus Interconnect

? Synopsys 2013

23

Sentaurus Interconnect Tool Overview
? Focus on BEOL device structures
Mechanical Stress Electro-Thermal

Fracture Mechanics
Crack

TSV Proximity

? Synopsys 2013

24

Sentaurus Interconnect Simulation Flow
Process Info
Deposition material=Oxide Etch mask=Metal_2

Layout Info GDSII
ICWB-EV Plus

Sentaurus Interconnect
Realistic 3D Structures with :
TSV Stress

Material Property Database

? Mechanical Stress Fields ? Electrostatic Potential ? Current Density ? Thermal hot-spots ? Mobility Variations ? Crack Propagation
Stress

Current

Temperature

Crack

? Synopsys 2013

25

BEOL Structure Meshing

? Synopsys 2013

26

Self Heating and Temperature Gradients
300K

Silicon block with constant resistivity
Boundary conditions for Thermal Simulation

Current Flow
?

Self Heating and Temperature Gradient

Performing electrical and thermal simulation alongside stress simulation, using the same input file and structure setup helps evaluate reliability and performance trade-offs efficiently Self-heating simulation allows 3D-IC engineers to estimate impact on transistor performance and validate chip-level models for thermal-aware placement
? Synopsys 2013 27

?

300K

Sentaurus Structure Editor
? ? ? ? ? Geometrical operations Easy to use GUI Scripting language Advanced geometrical modeling with analytic doping definitions Direct interface to meshing engines

S-RCAD DRAM

CIS pixels with microlenses

TSV Structure

? Synopsys 2013

28

ACIS Geometry Kernel
? Based on boundary representation. ? An ACIS boundary representation is a hierarchical decomposition of the topology of the model into lower-level topological objects. ? A typical body contains faces, edges, vertices, and may also includes lumps, shells, loops, and wires.

Tessellation controls

? Synopsys 2013

29

Scheme Language
? ? ? ? ? ? ? ? Strings Lists Arithmetic Expressions Boolean Operations Loops Logical Operations Procedures System Calls

? Synopsys 2013

30

2D -> 3D Structure Construction

? Synopsys 2013

31

Layout Based Device Design

Loaded Layout

Resist for STI

Silicon etching

STI formation (oxide filling) and Polysilicon / gate oxide generation
? Synopsys 2013 32

Metal generation for contacts

Final boundary structure

Process Emulation Mode
? Translates processing steps into geometric operations ? Works only in 3D ? Commands not accessible from GUI ? Support for: ? Iso- & Aniso- Depo/Etch ? Placement of analytical profiles w.r.t mask ? GDS2 file loading ? Masks definition and Patterning

? Synopsys 2013

33

Process Emulation - 3D CIS Structure
? A Sentaurus Structure Editor (SDE) script was done to generate “boundary” and “doping” files for Sentaurus Mesh (S-Mesh) ? GDS2 file is loaded into SDE and layers are built out of GDS2 layers

(define GDSFILE "TCAD_PIXEL_v3.gds") (define CELLNAME "TCAD_PIXEL_v3") (define LAYERNAMES (list 'PWELL 'POLY 'ACT 'NO_PW 'NPLUS 'CONT 'PW_LVT 'MET1 'VIA1 'MET2 'VIA2 'MET3 'VIA3 'MET4 'ULENS 'PD1 'PD2 'SN1 'SN2 'SN3 )) (define LAYERNUMBERS (list '1:0 '8:0 '9:0 '17:82 '32:0 '34:0 '35:0 '40:0 '41:0 '42:0 '43:0 '44:0 '49:0 '50:0 '89:0 '92:82 '93:0 '94:0 '94:43 '94:95 )) (sdeicwb:gds2mac "gds.file" GDSFILE "cell" CELLNAME "layer.names" LAYERNAMES "layer.numbers" LAYERNUMBERS "sim3d" (list 0 -6000 6000 0) "scale" 1.0e-3 "domain.name" "SIM3D" "mac.file" "TCAD_PIXEL")

? Synopsys 2013

34

Process Emulation - 3D CIS Structure
? Geometry is built step by step using deposition/etch/patterning features of SDE ? Scripting language (scheme) allows full customization, using variables, lists, strings and built-in ACIS functions.
(define TSUB 7.0) (sdepe:add-substrate "material" "Silicon" "thickness" TSUB "region" "substrat") (sdepe:pattern "mask" "ACT" "polarity" "light" "material" "Resist" "thickness" 1 "aniso" "algorithm" "sweep" ) "type"

(sdepe:etch-material "material" "Silicon" "depth" 0.420
(entity:delete (find-material-id "Resist"))

"taper-angle" 5)

(sdepe:fill-device "material" "Oxide" "height" (+ TSUB 0.008))

(sdepe:pattern "mask" "POLY" "polarity" "light" "material" "PolySilicon" "thickness" 0.3 "type" "aniso" "algorithm" "sweep" )

? Synopsys 2013

35

Process Emulation - 3D CIS Structure
? SDE is based on ACIS (product from Spatial, Dassault-System) and allows complex solid modeling

?

Micro-lens is part of a sphere inserted on top of the CIS

? Synopsys 2013

36

Process Emulation - 3D CIS Structure + doping
? ? ? Doping from analytical or SIMS profiles Doping from 1D/2D or 3D process simulation Meshing with Sentaurus Mesh

? Synopsys 2013

37

Advanced Tool Operations
2D geometry sweep with SDE / 2D doping sweep with SnMesh
Resulting 3D mesh/profile:

2D submesh:
Definitions {
SubMesh “trench2D" { Geofile = "trench2D.tdr" }

Placements { SubMesh “trench2D" { Reference = " trench2D " EvaluateWindow { Element = SweepElement { Base = Polygon [ (0 20 3.3288) (8.2 20 3.3288) (8.2 20 -20) (0 20 -20)] Path = [ (8.2 20 3.3288) (8.2 22 3.3288) (8.21 22.1 3.3288) … ] }}}}

}

? Synopsys 2013

38

SnMesh - Quadtree/Octree Spatial Decomposition
(A) (C) (A) Quadtree algorithm - mesh step proportional to device size (B) Quadtree algorithm - mesh step not proportional to device size (C) Quadtree algorithm - non axis-aligned boundary (D) Octree algorithm mesh step proportional to device size

(B)

(D)

? Synopsys 2013

39

Unified (octree/quadtree + normal offsetting) Meshing Algorithm

Offsetting { noffset material "Silicon" "Oxide" { hlocal=0.002 } noffset material "Oxide" "Silicon" { hlocal=0.002 } }
? Synopsys 2013 40

Definitions { Refinement "R5" { MaxElementSize = ( 0.026 0.026 0.026 ) } } Placements { Refinement "GDJ_RP" { Reference = "R5" RefineWindow = Cuboid [(-0.2 -0.2 0) (0.20 0.2 0.5)] } }

Doping Deatomization
Particle "BoronParticles" { ParticleFile = "kmc_final.tdr" Species = "BoronActiveConcentration" ScreeningFactor = 3.5e6 AutoScreeningFactor Normalization }

? Synopsys 2013

41

Sentaurus Device Simulator
? ? ? ? General purpose multidimensional (2D/3D) device simulator Silicon, SiGe, Ge, SiC, III-V compounds (including III-N materials) Drift-diffusion, Hydrodynamic, Thermodynamic, and Monte Carlo transport Wide range of advanced physical models
– Stress-dependent mobility enhancement

– Quantization and random doping effects
– Circuit mixed-mode, small-signal AC, Harmonic Balance – Variability Analysis

STI Narrow Width Effect
? Synopsys 2013 42

FinFET

NAND Flash

CMOS Image Sensor

UMOS

Sentaurus Device for CMOS
? ? ? ? ? ? ? ? ? Carrier quantization in the channel Hydrodynamic transport Noise analysis High-k dielectrics Mechanical stress and strain effects Stochastic geometry and doping variability Remote Coulomb scattering Advanced surface mobility modeling Non-local band-to-band and impact ionization Gate leakage Energy dependent energy relaxation time Degradation kinetics IFM based variability analysis

50nm NMOS

IdVg

Line Edge Roughness Variability

? ?
? ?
Calibration to SIMS, Roll-off and Ion

? Synopsys 2013

43

Sentaurus Device for Memory
? ? ? ? ? ? ? ? ? ? ? Carrier quantization in the channel Spherical Harmonic Expansion Non-local tunneling Hot Carrier Injection 3D capacitive effects Multi State Configuration including the state dependent physical models and parameters Cycling analysis Mixed-mode simulations Advanced surface mobility modeling Non-local band-to-band, TAT, and impact ionization Interface trap degradation

SRAM inverter

NOR Flash

NAND Flash

DRAM Cell

SONOS/NROM

PRAM

? Synopsys 2013

44

Sentaurus Device for Power
? Thermodynamic carrier transport ? 3D geometry effects ? Mixed-mode simulations including the circuit protective elements, represented by compact models ? Heat dependent kinetic model parameters ? Non-local gate tunneling ? Trapping dynamic ? Composition dependent model parameters ? Heterointerface carrier transport ? Carrier thermionic emission ? Carrier quantization in the channel ? Piezo and spontaneous polarization ? Doping Incomplete Ionization ? Material anisotropy

ESD Protection IGBT

UMOS P-LDMOS

III-N HFET

SiC VJFET

? Synopsys 2013

45

Sentaurus Device for RF
HBT
III-V HEMT

? ? ? ? ? ? ? ? ? ? ? ?

Hydrodynamic transport Small-signal AC analysis Harmonic balance analysis Carrier quantization Bulk and interface traps Mechanical stress and strain effects Energy dependent energy relaxation time Anisotropy effects Composition dependent model parameters Non-local barrier tunneling Stress dependent models Polarization fields

? Synopsys 2013

46

Sentaurus Device for Optics
? Drift-diffusion carrier transport ? Advanced optical solvers:
? ? ? ? Transfer Matrix Method Beam Propagation Method Raytracing FDTD Maxwell solver

Si, Ge mc-Si, a-Si GaAs, InGaP, … CIGS, CdTe

Solar Cells

CMOS Image Sensors

? 3D geometry effects ? Mixed-mode simulations including the circuit periphery elements ? Carrier trapping ? Composition dependent model parameters ? Heterointerface carrier transport ? Advanced models for photon and free carrier absorption ? Organic semiconductors

CCD

Photodetectors

? Synopsys 2013

47

Sentaurus Visual - New TCAD Visualization Platform
? Visualization product for 1D, 2D and 3D plots and structures generated by all TCAD tools

? Synopsys 2013

48

Sentaurus Visual - Enhanced GUI
? Better utilization of GUI real estate

Adjustable Frame Size Dockable Frames

? Synopsys 2013

49

Sentaurus Visual - Tcl Scripting Interface
? Powerful TCL Interface Consistent with Scripting Capabilities in other Sentaurus TCAD tools

?

TCL Script For Corresponding GUI Action

Active TCL Command Window
Saving TCL Script to File

? Synopsys 2013

50

Sentaurus TCAD
Radiation Analysis

? Synopsys 2013

51

Radiation Environment
? Single Event
– Due to single ionizing particle (alpha particle, heavy ion or neutron) , generation of electron-hole pairs in semiconductors – Leading to Soft-Error as Single Event Upset (SEU) – Leading to Hard-Error as Single Event Gate Rupture (SEGR), LatchUp (SELU) or Breakdown (SEB)

? Total Dose
– Due to long radiation exposure (nuclear power, aerospace), resulting in trapped carriers in insulators – Leading to performance degradation (increased leakage current, threshold voltage shift)

? Synopsys 2013

52

Sentaurus Device Models: Particle Interaction
? Alpha Particles
– Analytical description of the carriers generation depending on the incident particle energy – 3D cylindrical distribution

? Heavy Ion
– Analytical description of the carriers generation depending on the incident ion – Spatially defined charge description through LET – 3D cylindrical distribution

? Synopsys 2013

53

2D vs 3D Description of Charge Track

2D Extrusion: Unphysical Track

Full 3D: Realistic Track

+ + ++ + + ++ ++ + + + + + + +

+ + ++ ++ ++ + ++ + + + + + +

? Synopsys 2013

54

Sentaurus Device Heavy Ion Model
Electron-hole generation rate:
? ? t ? time ? 2 ? ? ? 2 ? exp ? ? ? ? ? ? shi ? ? ? ? ? shi ? ? time ? ? ? ? ?? 1 ? erf ? s ? ?? ? ? hi ? ? ?

G(l , w, t ) ? T (t ) ? R(w, l ) ? GLET (l )

T (t ) ?

w ? ? ?? ? ? w (l ) ? ? t ? ? ?e R( w, l ) ? ? ? w ? ? ? ? ?e ?? ? wt ( l ) ? ?

GLET (l ) ? a1 ? a2 ? l ? a3e a4 ?l ? k ? c1 ? (c2 ? c3 ? l ) c4 ? LET _ f (l )

?

?

time

Bragg peak

s
Rate Rate

wt
Rate
0 Radial distance

0

1

2

3 Time

4

5

6

0 Distance along track

? Synopsys 2013

55

Simulation of Charge Track
Physics { Recombination ( SRH(DopingDep) ) HeavyIon ( Direction = (0,0,1) Location = (0.5,0,0.7) Time = 1.0e-13 Length = [1e-4 1.5e-4 1.6e-4 1.7e-4] LET_f = [1e6 2e6 3e6 4e6] wt_hi = [0.3e-4 0.2e-4 0.25e-4 0.1e-4] Exponential ) }

Lmax

w(L)

? Synopsys 2013

56

Models for Total Dose Radiation
? Electric-Field Dependent Yield Function ? Self-Consistent Trapping Kinetics in Oxide:
– Standard V-model based on carrier concentration – Proprietary J-model based on carrier current

? Spatial Distribution of Traps
– Region or interface-wise – User defined profile

? Arbitrary Energy Spectra of Traps ? Electric-Field Dependent Cross Section ? Thermal Ionization of Traps

? Synopsys 2013

57

Mixed-Mode Simulation
? ? Sentaurus Device is a device and circuit simulator Allows numerical devices to be embedded in SPICE netlist

? Synopsys 2013

58

Mixed-Mode Compact Models
? Standard SPICE Models
– BJT

– Berkeley SPICE 3 Version 3F5 models
– BSIM1, BSIM2, BSIM3, BSIM4 – B3SOI

– MESFET

?

User-Defined
– Compact model interface (CMI) available for user-defined models.

– Implemented in C++ and linked to executable at run-time

? Synopsys 2013

59

Sentaurus Advantages for Rad-Hard
? 1D / 2D / True 3D ? DC, AC, Transient ? Most Advanced Transport Models in Semiconductors and Insulators ? Mixed-Mode: Numerical and SPICE Models ? Robust Numerical Algorithms ? Parallel Solvers ? Dynamic Memory Allocation ? Physical Model Interface

? Synopsys 2013

60

2D Application Examples

? Synopsys 2013

61

Total Dose Effect: SOI nMOSFET
SOI nMOS transistor structure Drain current vs. irradiation time

The leakage current increases with the dose and drain bias showing electric field dependence
? Synopsys 2013 62

Total Dose Effect: SOI nMOSFET
Electron Current Density in SOI Device after Irradiation

Expected back-channel in irradiated SOI nMOS devices is observed

? Synopsys 2013

63

Total Dose Effect: SOI nMOSFET
Trapped Hole Distribution in Irradiated Device

Because of self-consistent and field-dependent trapping kinetics, trapped hole distribution strongly depends on electric field
? Synopsys 2013 64

Total Dose Effect: SOI nMOSFET
Transient Evolution of Trapped Hole Density after Irradiation

Sentaurus Device enables the modeling of de-trapping, depending on the energetic distribution of traps
? Synopsys 2013 65

3D Application Examples

? Synopsys 2013

66

Structure Generation

Loaded Layout

Resist for STI

Silicon etching

STI formation (oxide filling) and Polysilicon / gate oxide generation
? Synopsys 2013 67

Metal generation for contacts

Final boundary structure

Doping Definition
? Constant doping profile in Polysilicon and Pwell

? Analytical doping profile (Gaussian) in the Source/Drain of NMOS and PMOS Transistors
? Analytical doping profile (Gaussian) in the channel of NMOS and PMOS Transistors ? Analytical doping profile (Gaussian) in the access drain (bit line) and access gate (word line).

? Synopsys 2013

68

Meshing
? Meshing strategy: ? Refinement on doping (junctions refinement) ? Refinement at Silicon / Gate Oxide interface

? Refinement in the channel of NMOS and PMOS Transistors.
? Relaxed mesh inside the substrate ? Mesh statistics: ? Mesh nodes number: 31825 ? Meshing time: 114 s

? Synopsys 2013

69

Bit Flipping
? At t=1e-13s Vds(nmos2)=1.5V and Vds(nmos1)=0V.
? The peak of the Gaussian Distribution of Heavy ion is at 1e-11s. ? At t=1e-8s, Vds(nmos1)=1.5V and Vds(nmos2)=0V. ? The SRAM cell switched states

Node voltages versus time for NMOS drains as a result of a single event strike. The SRAM cell switched states

? Synopsys 2013

70

Generation Rate from Particle Strike
T=10ps T=15ps T=20ps

T=40ps

T=80ps

T=160ps

? Synopsys 2013

71

Dependence on Impact Points
? The heavy ion direction is set to (0, 0, -1).

? Four different heavy ions impact points are simulated:
? Source NMOS2

? Source PMOS2
? Drain PMOS2 ? Oxide ? The SRAM cell does not switches states anymore for impact points in Source & Drain PMOS2 and in the oxide.

Node voltages versus time for NMOS drains as a result of a single event strike. Depending on the impact point ,the SRAM cell switched states

? Synopsys 2013

72

Total Dose Effect: 3D SOI nMOSFET
Trapped Hole and Electron Current Distributions in 3D SOI nMOS after 300kRad Irradiation

Expected trapped hole profile in the buried oxide and induced back-channel are observed in 3D
? Synopsys 2013 73

Total Dose Effect: 3D nMOS w/ LOCOS
Noffset meshing of 3D MOS with LOCOS Trapped hole density after 10kRad irradiation

Noffset3D, normal offsetting mesh, creates fine grid along the interfaces where traps are located
? Synopsys 2013 74

Total Dose Effect: 3D Trench MOSFET
Threshold Voltage Shift Geometry and Doping Drain Current vs. Gate Voltage

? Synopsys 2013

75

CMOS SOI
SEU: SOI SRAM Cell Upset
Voltage response for different ion energies

3D charge deposition profile

SEU can be accurately modeled using a mixed-mode approach including part of the system as SPICE elements
? Synopsys 2013 76

SEU: 3D SRAM Cell Upset
3D SRAM structure Node voltage response for 2 heavy ion energies

As expected, the three dimensional SRAM flips depending on the incident particle energy, the ion strikes into the drain of the off-nMOS
? Synopsys 2013 77

SEU: CMOS Inverter Latch-up
CMOS inverter structure Current response for 2 LETs Ion impact on CMOS structure

Because of parasitic bipolar effects in CMOS structure, the device latches up when incident particle energy is high enough
? Synopsys 2013 78

Thank You

? Synopsys 2013

79


相关文章:
更多相关标签: