Presentation is loading. Please wait.

Presentation is loading. Please wait.

ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-1 ECSE-6230 Semiconductor Devices and Models I Lecture 3 Prof. Shayla M. Sawyer Bldg.

Similar presentations


Presentation on theme: "ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-1 ECSE-6230 Semiconductor Devices and Models I Lecture 3 Prof. Shayla M. Sawyer Bldg."— Presentation transcript:

1 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-1 ECSE-6230 Semiconductor Devices and Models I Lecture 3 Prof. Shayla M. Sawyer Bldg. CII, Room 8225 Rensselaer Polytechnic Institute Troy, NY Tel. (518) FAX (518)

2 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-2 MEDICI Lecture Created by Jeff Langer Edited by Peter Losee (F05), Kamal Varadarajan (F07) and Vipindas Pala (F10)

3 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-3 Overview Using ECSE servers –Logging in using SSH/Remote Desktop MEDICI Tutorial –Simulator overview –MEDICI Example – Silicon pn junction diode

4 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-4 Remote Access Login remotely from your laptop –Login to any of : ts1.ecse.rpi.edu ts2.ecse.rpi.edu ts3.ecse.rpi.edu ts4.ecse.rpi.edu ts5.ecse.rpi.edu Remote Desktop –Windows XP / Older - Use remote desktop client –Windows 7 / Vista use the XP remote desktop client SSH –From any terminal (Mac / Linux) –PUTTY for windows –From windows use an X-Window Client for to port graphics

5 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-5 Remote Access Note if logging in from off-campus, VPN in first If there are problems logging in with ts1…try any other of the machines, ts2, ts3, ts4, ts5

6 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-6 MEDICI Introduction : What A physics based device simulator –Output I-V curves, capacitances, electrode charges (DC) Gain, Capacitances, S Parameters (AC) Light (Optical) Solves simple circuits (CMOS Inverters etc) Visualize internal physics (Carrier densities, carrier velocities, ionized charges, recombination/generation, …… ) –Input Device Geometry (2D) Material properties (Doping, Mole Fractions, Mobilities …) Originally developed in Stanford University (PISCES - Poisson and Continuity Equation Solver) Similar tools : MEDICI, DESSIS, ISE, ATLAS, Sentaurus

7 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-7 MEDICI Introduction : Why Modeling of device behavior –Understand mechanisms behind characteristics –Study extreme behavior like breakdown when measurement is difficult Help understand the process corners –Because fabrication is never perfect –A typical question : How sensitive is the transistor gain to variation in doping ? Device Optimization –Reduces the number of process spins and cost –Experiments with process are costlier and take more time And most importantly, device design –Try your ideas without going through a fabrication process (play with geometry, materials) –A success in simulation does not guarantee a good prototype – models can capture most of physics but not all.

8 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-8 MEDICI Introduction : How Finite element analysis –Divides the structure into a bunch of small triangular segments (grid) –Solves Poissons and Continuity Equations numerically for each grid point Poissons equation : Electrostatics Current into a volume – Current out of a volume = Charge generated – Charge recombined –Models : Carrier transport (mobility) Carrier generation recombination : SRH, Auger (or Impact Ionization), Radiative Quantum effects (Fermi statistics) : Can also solve Schrodingers equation if needed –Materials : Silicon (easiest, can use default material parameters), Ge Compound semiconductors : SiGe, GaAs. GaN, SiC

9 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-9 MEDICI Introduction : How Current version of MEDICI includes modules which allow – Anistropic modeling – Circuit analysis – Optical device simulation – Variable lattice temperature simulation – Hetero-junction simulation – Programmable device simulation

10 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-10 Simulation Procedure Device Structure Definition Defined using a text file Use an editor (vi, emacs, gedit) Device Simulation Run program : Apply bias conditions, run DC / AC / Transient simulations Simulation time depends on : number of grid points, complexity of models Analysis 1D Plots : Output currents, voltages 2D Plots : Physical variables (carrier concentration etc) for each grid point

11 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-11 Getting Started First, grab the manual ! –Location : in your account folder –Run an example code or two: under Medici_examples, also in account folder To run Medici: –md3200 (or medici) file-maximum 3,200 grid points –md10000 file - 10,000 maximum grid points –md20000 file - 20,000 maximum grid points –For example: md3200 diode.inp

12 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-12 Suggested Procedure for Simulation Define structure and save to file, e.g. –MESH OUT.FILE=filename.GRD –SOLVE OUT.FILE=filename.SOL (zero bias solution) Simulate device and save data to files –Load structure –MESH IN.FILE= filename.GRD –LOAD IN.FILE= filename.SOL –Saving data –IV Data => LOG OUT.FILE= filename.IV –Grid Solution=> SOLVE v1=0 v2=0.1 OUT.FILE= filename.01

13 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-13 Suggested Procedure for Simulation (cont.) Plotting results –Load structures with MESH –Load grid solution with LOAD –Plot data, e.g. for IV/It, Vt

14 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer Create the mesh MESH, X.MESH, Y.MESH 2. Define material and electrode regions REGION, ELECTR (0,0) y x 3. Specify Impurity Profiles PROFILE Sets impurity type, concentration and distribution including uniform, gaussian (default) or erfc 1. Define Device Structure

15 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer Define Device Structure (cont.) 4.(Cont.) INTERFACE – QF - Interface fixed charge – CLEAR - No interface fixed charge (default) 5.Set mobility and material parameters MOBILITY MATERIAL

16 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer Define Device Structure (cont.) 4.Set up contact and interface characteristics CONTACT – Resistance lumped – Metal – Metal work-function – Barrier lowering – Surface recombination velocity

17 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer Simulate Device 1.Specify physical models MODEL 2.Specify method of solution SYMBOLIC METHOD 3.Set up file for logging IV data LOG OUT.FILE=filename.iv

18 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer Simulate Device (cont.) 4.Solve device structure SOLVE Specify electrode voltages Specify transient simulation parameters (e.g. time step, ramp time) Specify output file name for solution to structure OUT.FILE=filename

19 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-19 Types of available plots I-V Distribution (e.g. potential, electric field, carrier conc.) Transients Contour plotting Plot commands PLOT.1D, PLOT.2D, PLOT.3D, 3D.SURFACE, CONTOUR, LABEL, CALCULATE, EXTRACT 3. Analysis of Simulation

20 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-20 Complete example can be found on MEDICI Manual page 6-1 (mdex3) Diode & Lumped Elements Example This example has been modified to show the I-V characteristics of a Silicon pn junction diode along with the hole concentration in the n-type region of the diode at forward bias (on-state) With any text editor (pico, emacs, wordpad, vi etc.) create or save the following file shown on the next 3 slides Example: Silicon pn Diode

21 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-21 Example: Silicon pn Diode TITLE Avant! MEDICI SDM-I Class Example - Diode I-V Simulation COMMENT Create an initial simulation mesh MESH X.MESH X.MAX=3.0 H1=0.50 Y.MESH Y.MAX=3.0 H1=0.25 COMMENT Region and electrode statements REGION NAME=Silicon SILICON ELECTR NAME=Anode TOP X.MAX=1.0 ELECTR NAME=Cathode BOTTOM $ Specify impurity profiles PROFILE N-TYPE N.PEAK=1E15 UNIF OUT.FILE=MDEX3DS PROFILE P-TYPE N.PEAK=1E19 X.MIN=0 WIDTH=1.0 X.CHAR=.2 + Y.MIN=0 Y.JUNC=.5 $ Refine the mesh with doping regrids REGRID DOPING LOG RAT=3 SMOOTH=1 IN.FILE=MDEX3DS + OUT.FILE=SDM1MSH

22 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-22 PLOT.2D GRID TITLE="SDM-1 Diode Exmaple - Simulation Mesh" SCALE FILL COMMENT Specify physical models to use MODELS SRH AUGER CONMOB FLDMOB COMMENT Symbolic factorization SYMB NEWTON CARRIERS=2 COMMENT Create a log file for the static I-V data LOG OUT.FILE=IV_LOG_FILE COMMENT Perform a 0-volt steady state solution, then simulate $ the static I-V characteristics for the diode. SOLVE OUT.FILE=ZERO_BIAS_SOL PLOT.3D DOPING LOG + TITLE="SDM-I Si Diode 3-D Doping Profile" SOLVE ELEC=ANODE NSTEP=15 VSTEP=0.05 SOLVE V(Anode)=0.75 OUT.FILE=V_AN_1_SLN Example: Silicon pn Diode

23 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-23 COMMENT Plot the diode current vs. anode voltage PLOT.1D X.AXIS=V(Anode) Y.AXIS=I(Anode) + POINTS + TITLE="SDM-I Si Diode I-V Trace Example" + COLOR=2 LOAD In.file=V_AN_1_SLN PLOT.1D holes x.start=0.5 x.end=0.5 y.start=0.5 y.end=3 POINTS + TITLE="Hole V(Anode)=0.75V, X=0.5, Y=0 to Y=3" + COLOR=2 PLOT.2D FILL CONTOUR FLOWLINES LINE.TYPE=3 COLOR=2 NCONT=20 Example: Silicon pn Diode

24 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer st PLOT Statement : PLOT.2D Shows the mesh structure Example: Silicon pn Diode

25 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer nd PLOT Statement : PLOT.3D Shows the doping profile Example: Silicon pn Diode

26 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer rd PLOT Statement : PLOT.1D Shows the simulated I-V curve Example: Silicon pn Diode

27 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer th PLOT Statement : PLOT.1D Shows the simulated hole concentration in the n-type region under forward bias Example: Silicon pn Diode

28 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer th PLOT Statement : PLOT.2D with CONTOUR Shows the simulated current flow-lines at forward bias Example: Silicon pn Diode

29 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-29 AIM-SPICE Lecture Outline AIM-SPICE Tutorial and Links AIM-SPICE Modeling Practical Applications Comparisons Summary

30 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-30 Tutorial: AIM-SPICE Automatic Integrated Circuit Modeling Spice Download from Tutorial, Manual, and Download found on my website under AIM-SPICE download and AIM- Spice Tutorial Two books for reference –T. A. Fjeldly, T. Ytterdal, and M. Shur, Introduction to Device Modeling and Circuit Simulation, John Wiley & Sons, New York, (1998), ISBN –K. Lee, M. Shur, T. A. Fjeldly, and T. Ytterdal, Semiconductor Device Modeling for VLSI, Prentice Hall, Englewood Cliffs, NJ (1993),

31 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-31 AIM-SPICE Device models are defined in terms of equivalent circuits consisting of circuit elements such as current sources, capacitances, resistances etc. Based on Berkley SPICE created in 1972 A vehicle for the new set of advanced device models for circuit simulation

32 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-32 Tutorial: AIM-SPICE A circuit should be drawn (schematic) to determine nodes that define every device that is part of the circuit Nodes must be numbered Circuit is described by a sequence of lines that consist of statements that are responsible for: –definitions of power supply sources –single element or device –model parameters –Specification for output to be analyzed or analysis types

33 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-33 Tutorial: AIM-SPICE Input format is as follows: Circuit Title Power Supplies Signal Sources Device/Element Descriptions Model Statements In order to run the simulation the devices (with devices with specific models) commands have to be included with a dot in front of the model command line Order is arbitrary except for circuit title and model statements

34 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-34 Tutorial: Basic Example The SPICE model for the AC circuit below AC circuit vin ac r k r k c n Click AC icon. For AC Analysis Parameters enter the following: Click LIN Number of points = 1000 Start frequency = 0 End frequency = 200k Variables to plot, magnitude plot and v(2) voltage, Go to control and click start Simulation, Auto-Scale C2C2 R2 R1 vin 1 2

35 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-35 The SPICE model for a DC sweep: Diode circuit below simple diode vd 1 0 dc 0 d1 1 2 diode vid 2 0 dc 0.MODEL diode d level=1 Click DC icon. For DC Transfer Curve Analysis Parameters: Click 1. Source (default) Source name: pull down vd Start value = -5 End Value = 5 Variables in circuit i(vid) current (acts as ammeter to circuit), Go to control and click start Simulation, Zoom over region Tutorial: Basic Example vd vid 0 1 2

36 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-36 Tutorial: Device Basic Example Run the following nMOS circuit using the DC tool to give a DC analysis. The number code for a MOSFET is Name D G S B that is (m ) in this case shown below nMOS resistor circuit vdd 3 0 dc 3 vgs 1 0 dc 1.0 *the voltage source vid is inserted to be used as an ammeter vid 3 2 dc 0 rd k m ntype l=1.0u w=4.0u.model ntype nmos level=2 vto=0.5 kp=25e-6 Draw the schematic of this circuit

37 ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-37 Tutorial: Device Basic Example DC analysis parameters 1. Source Source Name: vdd Start Value: 0 End Value: 1.0 Increment Value: Source (Optional) Source Name: vgs Start Value: 0 End Value: 1 Increment Value: 0.1 Select variables to plot drain current i(vid) Start simulation and autoscale


Download ppt "ECSE-6230 Semiconductor Devices and Models I Fall, 2012 S. Sawyer 1-1 ECSE-6230 Semiconductor Devices and Models I Lecture 3 Prof. Shayla M. Sawyer Bldg."

Similar presentations


Ads by Google