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A Platform for Compact Model Sharing!
Hao Wang, Mansun Chan!
Department of ECE, HKUST!
interactive Modeling and Online Simulation Platform
THE ROLE OF COMPACT MODELS!
Multi-Gate MOS Nanowire MOSFET
Scaling MOSFET
VBIC
HiCUM BSIM
Mextram
ACM
HiSIM
USIM
PSP
HVEKV
MM20
Spectre Eldo
ADS Smash
Nanosim
HSIM
APLAC
AMS Golden Gate
HSPICE
v Device à Models à Simulator à Applications
CURRENT MODELING INFRASTRUCTURE!
Experimental data, Parameter Extraction
Model 1
Model 2
Model 3
Coding, Testing, implementing to a
simulator
Circuit Simulation
Technologist Modelers
Implementation, Compiling, Evaluate
Models, obtain parameters
Designers Applications
STATUS OF PUBLISHED MODELS!
v Some only describe a single quantity (like threshold voltage) rather than a complete model!
v Some have implicit functions that require numerical solution!v Some models have discontinuities between different
section of the characteristics!v Some have poorly behaved derivatives !v Some do not have charge and capacitance model!v Some do have an explicit parameter set !v Convergence issues of most models are not tested!v No follow-up after publication !
A REVOLUTIONARY DISTRIBUTION CONCEPT!
v The App store has significantly shorten the distance between programmer and users since July 11, 2008!
v Can we have an App store for compact models?!
AN APP STORE FOR COMPACT MODELING!
Foundry
Circuit
designer
EDA vendors
Model developer
Model extracted
Simulator implementation
Design verified
Simulation flow verified
i-MOS
v A project started in June 2011 !
THE i-MOS PROJECT!
v It stands for interactive Modeling and Online Simulation!v Intended to be a social network for the compact modeling
community including both developers or just users!v Provide a platform for model developers to distribute their
models!v Provide a platform for users to evaluate models!v A place to discuss modeling related issues!v A source for updated modeling activities!v It runs under a user driven model with light moderation!
COMPONENTS OF i-MOS!
Browser Interface User
authentication User Input
Simulation Instruction
Ngspice Simulation Engine
Output Variables
Parameter Library
Graphic user interface
Output to Users
i-MOS Platform
MODEL IMPLEMENTATION!
registered as a model developer
defining model pages with standard templates
Submit model Verilog-A code
Model Verification
Compilation with ADMS
Internal qualification process
Output to the i-MOS system
qualification process
model development server
user execution and feedback
i-MOS server currently done by
hand
THE NGSPICE ENGINE!
v From de facto standard simulator SPICE!
CANCER ’70s SPICE1,2 SPICE3 ’80s SPICE3f5 ’90s Ngspice 00’s
v Many standard device models have already been included!v It has a specific C interface!
Hierarchy
Model code ���mld.c, macld.c, ���mtemp.c …
Model setup ���m.c, mdel.c ���mset.c …
Model I/O ���mask.c, mpar.c���
mic.c …
THE ADMS VERILOG-A COMPILER!
v Verilog-A has become the standard modeling language!
v ADMS!
Ø Developer friendly!
Ø Interpreted code has lower efficiency than C-code!
Ø Widely used for new models!
Ø Convert Verilog-A to C-code!
Ø Partial derivation for Jacobian matrix!
Ø Model/instance setup API!
Ø Similar efficiency to hand code!
THE NGSPICE INTERFACE!
Hierarchy
manalogfunction.c ���m.hxx ���
mguesstopology.c
Model code ���mld.c, macld.c, ���
mtemp.c…
Model setup ���m.c, mdel.c ���mset.c …
Model I/O ���mask.c, mpar.c���
mic.c …
<admst:text format="IFparm $(module)mPTable[] = {\n"/> <admst:join select="variable[parametertype='model' and input='yes']" separator=",\n"> <admst:choose> <admst:when test="[type='real']"> <admst:value-‐of select="name"/> <admst:value-‐of select="name"/> <admst:value-‐of select="name"/> <admst:text format=" IOP("%s",$(module)_model_%s,IF_REAL,"%s")"/> </admst:when> <admst:when test="[type='integer']"> <admst:value-‐of select="name"/> <admst:value-‐of select="name"/> <admst:value-‐of select="name"/> <admst:text format=" IOP("%s",$(module)_model_%s,IF_INTEGER,"%s")"/> </admst:when> <admst:otherwise> <admst:fatal format="parameter of type 'string' not supported\n"/> </admst:otherwise> </admst:choose> </admst:join> <admst:text format="\n};\n"/>
IFparm cnt_mPTable[] = {
IOP("pnp",cnt_model_pnp,IF_INTEGER,"pnp"),
IOP("npn",cnt_model_npn,IF_INTEGER,"npn"),
IOP("phisb",cnt_model_phisb,IF_REAL,"phisb"),
IOP("rs",cnt_model_rs,IF_REAL,"rs"),
IOP("rd",cnt_model_rd,IF_REAL,"rd"),
IOP("beta",cnt_model_beta,IF_REAL,"beta"),
IOP("cc",cnt_model_Cc,IF_REAL,"Cc"),
IOP("mob",cnt_model_mob,IF_REAL,"mob"),
IOP("csubfit",cnt_model_Csubfit,IF_REAL,"Csubfit"),
IOP("cp",cnt_model_Cp,IF_REAL,"Cp")
};
parameter real phisb = 0 from (-‐inf:inf) `P(info="Barrier Height");
parameter real rs = 0 from (-‐inf:inf) `P(info="Source Access resistance"); parameter real rd = 0 from (-‐inf:inf) `P(info="Drain Access resistance"); parameter real beta = 20 from (-‐inf:inf) `P(info="Drain coupling coefficient"); parameter real Cc = 7e-‐12 from (-‐inf:inf) `P(info="Coupling capacitance"); parameter real mob = 1 from (-‐inf:inf) `P(info="Scattering parameters"); parameter real Csubfit = 1 from (-‐inf:inf) `P(info="Vfb adjustment parameter"); parameter real Cp = 0 from (-‐inf:inf) `P(info="Parasitic capacitance");
admsXml –I(srcdir) –I(srcdir)/admsva $(srcdir)/admsva/m.va –e ngspiceMODULEtempale.xml
ngspiceMODULE.c.xml
m.va
m.c
v An authoring kit is being develop to automate the process!
BENEFITS TO MODEL USERS!
v i-MOS made many device models available for early access without the need of compilation and execution on a local machine!
v Run simulations and do demonstrations anywhere !v Able to directly compare the completeness and
performance of different models!v Uniform GUI with low learning barrier!v Come with standard parameters, benchmark, test circuits!v One stop service to model documents and modeling
activities!
i-MOS SIMULATION INTERFACE!
v Users will be allowed to comment on models soon!
MODELING RESOURCES!
v You are welcome to post your modeling activities on i-MOS!
BENEFIT TO MODEL DEVELOPERS!
v Provide a standard on the requirements of a model, including I-V, Q-V, first derivatives, continuity, smoothness etc.!
v Provide a simple authoring tool to interface the model to a circuit simulation engine directly!
v Provide a simple and standard user interface to distribute models to users!
v Facilitate the user feedback process for model refinement and improvement!
v Promote interaction between model developers and users through various channel of discussion!
MODELS IMPLEMENTED IN CURRENT SYSTEM!
Device Type Group Availability
Symmetric Double Gate MOSFET
HKUST/Peking University
Online
Silicon Nanowire Transistor
HKUST/Peking University
Online
AlGaN HEMT Tsinghua University Online
CNT FET Arizona University Online
CNT FET Stanford University In Progress
Phase Change Memory HKUST In Progress
v If you want your model to be included in i-MOS, please let us know!
BENEFITS TO EDA VENDORS!
v Provide early access to new device models!v Evaluate and compare models under the same platform
using standard GUI !v Collect user feedback to obtain popularity of various models
based on model rating!v Provide a platform to communicate with model developers!v Provide parameter extraction service for a given model from
foundry data!v Gain access to parameter sets from various sources (either
as transparent data or blackbox plugin)!
ISSUES TO RESOLVE!
v Current version of ADMS only support a subset of Verilog-A syntax !
//allowed in ADMS I (a,b) <+ V (a,b) ) / R; //not allowed in ADMS
V(a,b) <+ I (a,b)*R;
Ø V(..) <+ xxx not supported!
Ø I (..) probes not supported!
Ø For loop not supported!
v XML script of ADMS poorly documented !v Human interface need for some time before all the tools are
ready!
OTHER SERVICES TO BE LAUNCHED!
v Automated Model Authoring kits!v Modeling rating and commenting!v Discussion group and professional networking!v Parameter extraction!v Standard parameter set!v Standard test results!v Online simulation (slightly longer term)!
Ø Phase I, input by submitting netlist text file!
Ø Phase II, complete circuit simulation GUI!
A QUICK PREVIEW OF THE UP COMING SERVICES!
P1 P2 P3 P4
User comments
Upload data and extract parameters
User Comments!
Upload Data and Extract Parameters !
(depends on availability of
extractor)!
Pre-defined/saved parameters !(blackbox
parameters allowed)!
Modeling Rating!
v If there is any service you think is useful to you, please let us know!
PLEASE TRY OUT OUR SERVICE !
v Please visit the following site:!
http://i-mos.org!
v You will be able to try out our service after a simple and free registration!
v It is not perfect at present stage and we appreciate your tolerance!
THE i-MOS TEAM!
v Principle Investigator: Prof. Mansun Chan !
v Research Students:!v Project Manager: Dr. Hao Wang!
Ø Lining Zhang!Ø Xiaoxu Cheng!
v Collaborators:!Ø Prof. Jin He, Peking University!Ø Prof. Philip Wong, Stanford University!Ø Prof. Yan Wang, Tsinghua University!Ø Prof. Yu Cao, Arizona State University!
v Funding: Hong Kong UGC AoE/P-04/08!
THE BEGINNING!
THANK YOU!!
