Synopsys Sentaurus Tutorial - For EE 130/230M Project Dr. Nuo Xu Spring 2013

CONFIDENTIAL INFORMATION The following material is being disclosed to you pursuant to a non-disclosure agreement between UC Berkley 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.

Outline Software Setups and Configurations Introduction to Sentaurus TCAD Basic Sentaurus Operations Project Tips

Software Setups X11 Forwarding Software (i.e. Exceed) Successful running will display a task bar on your desktop Exceed helps you forward the GUIs from Unix system to your PC

Software Setups You may also use Xming that is loaded on the computer lab (1st floor of Cory Hall). Putty WinSCP Putty is a remote login software, will help you to log into Unix system from a PC (Windows) WinSCP can be downloaded online, for free, and is used to transfer files from your PC to the Unix.

Servers and Performance Instructional servers (login with the instructional accounts): pulsar.eecs.berkeley.edu quasar.eecs.berkeley.edu c199.eecs.berkeley.edu Shared servers are going to be slow, due to the multiple-thread tasking. Do not wait until the last day! For those who want to WFH: The connection speed is going to be slow, if you are off campus and do the direct forwarding from the servers. My suggestion: leave a computer on campus running Sentaurus and remote log into it.

Configurations .cshrc file A system configuration file under your folder, to define all the environmental variables needed in Unix system Append the following codes to the bottom of your existing .cshrc file: X11 Forwarding Make sure you have enabled the X11 forwarding option in putty. setenv LM_LICENSE_FILE 27005@license-srv.eecs.berkeley.edu set path = ($path /usr/eesww/synopsys/G_2012.06/bin) setenv STDB $HOME/SYNOPSYS/STDB

Please check here !

Running Sentaurus Start Exceed or Xming Start putty Select the server you want to run your simulation Log on the server Input your Account name and Password After you enter your login name, the system displays “Access Denied”. Ignore it and go ahead to enter your password.

Transfer of Project Folder to Unix Copy the project folder provided on the project link of class website to the instructional server by using WinSCP (see next page). After transferring the folder, type: scp -r Project username@pulsar.eecs.berkeley.edu This command will copy the Project folder into yout home directory

Log in using your instructional account! Once you have logged in, you can view the files in both your PC and the home directory of the server Log in using your instructional account! Just select the files/folder from your PC and copy to the server

- After login and file transfer, go back to your Putty window. - It’s recommended that you first check whether you have correctly configured your simulation. So type “which swb” It tells you the installation path of Sentaurus. - Then, type “swb” to start Sentaurus workbench.

Running Sentaurus on ilinux1 1. Copy project folder: scp –r project_dir username@ilinux1.eecs.berkeley.edu 2. Login: ssh -X username@ilinux1.eecs.berkeley.edu 3. Make a new directory at your home directory with: mkdir ee130_project 4. Copy the project folder in this newly made direcoty with: cp –r 20nm-NMOS-EE130 ee130_project 5. Start Sentaurus with the command at the home directory: /share/b/bin/swb You do not need to modify .cshrc file. 6. Once Sentaurus starts, first, from the left panel right click->project->unlock Then double click the project to see the modules loaded on the workbench. Now you can preprocess, run and visualize the results. For Windows: install MobaXterm from http://mobaxterm.mobatek.net/. On MobaXterm, you have a unix like command line using which you can login using the same unix like commands as above.

Sentaurus Workbench Run command: swb Graphical user interface to unify all simulation tools into a single experiment project flow Used to organize projects and set up experiments for both structure generation and device simulation Technology Computer-Aided-Design Tools Parameter row Experiment column

Unlocking Workbench Double click 20nm-NMOS: the simulation modules will show up on the work bench If you cannot edit the value in the cell, then Right click 20nm-NMOS→ project→unlock :This will unlock the project for modification of values. Technology Computer-Aided-Design Tools Parameter row Experiment column

Sentaurus Structure Editor Recommended to run in workbench Run command (under putty): sde Structure Editor (1) generates the device structure (including the doping profiles) (2) Defines the electrical contact and (3) generates the meshing for numerical simulations. Parameters you may need to change/optimize for this project Gate oxide thickness (Xo, Units: um) MOSFET gate length (Lgate, Units: um) Spacer length (Lsp, Units: um) Channel Doping Concentration (ChanDoping, Units: cm-3) Source/Drain extension depth (XjExt, Units: um)

Sentaurus Device Recommended to run in workbench Run command (under putty): sdevice Sentaurus Device simulates the device performance by solving multiple, coupled physical equations based on the meshing. Inputs: gate voltage (Vgs), drain voltage (Vds), workfunction value Common Physical models: Si band structure (Ec/v, Nc/v and bandgap narrowing) Fermi-Dirac Statistics Poisson equation, continuity equation Band-to-band tunneling, R-G current Drift-Diffusion current, carrier mobility, velocity saturation

Sentaurus Inspect Recommended to run in workbench Used to automatically extract critical device performance parameters such as: Vt_lin Id_lin Vt_sat Id_sat I_OFF Also used to plot the Id-Vg and Id-Vd curves

Simulation Status Start Sentaurus, first select from the left project column, right-click to “preprocess”. Then you will find the nodes will display different colors, suggesting they have different properties. Here is a summary. Only colorful nodes will give you the simulation output. “Ready” means the current tool is free of syntax errors (You should see this since you are not allowed to modify the scripts). Right-click a certain Ready nodes to run, after a short period of time, you will find it changes to “done” or “failed”.

Basic Operations for Sentaurus Structure Editor Now you can view your simulation results if the nodes are done. Right-click the node in Structure editor, select Visualize → Tecplot SV (Select File) and choose msh.tdr file to view your device structure.

Basic Operations for Sentaurus Tecplot This slide help you familiarize the usage of Sentaurus Tecplot, this tool is for the visualization and profiles/contours extraction purposes. zoom-in tool Slice-cutting display adjustment Default units: um

Export the results from Tecplot: To get the data field, first, use Y-cut to get the 1-D slice; then select export → Inspect graph Export the results from Tecplot: As an image (.bmp)

Then Inspect will be started. Select the data field herein; Click File → Export → txt file You can read your saved data (.txt file) from your project directory

Basic Operations for Sentaurus Device Right-click the “done” node in Structure Device, select Visualize → Tecplot SV (Select File) and choose des.tdr file to view your device performance contours (vector fields). Current Density Linear region Saturation region

Basic Operations for Sentaurus Device Cont.’d Right-click the “done” node in Structure Device, select Visualize → Inspect (Select File) and choose IdVg_des.plt file to view your device performance curves. Choose Log Y or Linear Y here Device Terminals Most common plot combination is “gate: OuterVoltage” Outputs Use cursors to read the data value along the curve “drain: TotalCurrent”

Project Tips Typical Performance Figure-of-Merits Performance Specifications for this Project Performance Optimization Hints for a Short-Channel MOSFET

Idsat, Ilin and IOFF Idsat Ilin IOFF VDD Vds=VDD Vds=20mV IOFF, Idsat and Idlin are extracted automatically IOFF VDD

Threshold Voltage (Vt) Constant current definition of threshold voltage It = 100nA · W/Lgate W has default value of 1um for 2-dimensional device simulation Vth Vtlin and Vtsat are extracted automatically

DIBL and SS Sub-threshold Swing DIBL is defined as the threshold voltage difference divided by the drain bias between linear and saturation region . Sub-threshold Swing You are required to extract S and DIBL manually, from your optimized device !

Performance Specifications For students taking EE130, your goal is for the Low-Operating Power (LOP) technology; and you have to meet the following specs (at 20nm node): For students taking EE230M, your goal is for the Low-Stand-by Power (LSTP) technology; and you have to meet the following specs (at 20 nm node): - IOFF should be smaller than 1 nA/um. - ION should be larger than 400 uA/um. LOP Products: ~16% of Semi. mkt - IOFF should be smaller than 10 pA/um. - ION should be larger than 250 uA/um. LSTP Products: nowadays >20% of Semi. mkt

Hints for Your Optimizations Impacts of channel doping concentration (Nch): Increasing Nch generally helps to reduce IOFF, until it touches the band-to-band tunneling limits. On the other hand, high Nch will degrade the carrier mobility values, resulting in a low ION. Impacts of Junction Depth (Xj): smaller extension Xj helps to reduce IOFF, however it will result in a larger Source/Drain series resistance value to degrade ION. Impacts of SiN spacer width (Lsp): Wider spacer helps to reduce the impact from deep Source/Drain regions; however it will also result in the larger series resistance problem. So as you can see, there exist trade-offs to optimize ION/IOFF ☺

Project Hints Since our performance targets are mainly for ION and IOFF, so you should start working on the saturation-region device simulation first. Once you are able to meet the specs, then you should perform the linear-region device simulation to get the current and threshold voltage values, as well as to measure the DIBL value.

Project Hints (Con’d) The next task is to study the Short-Channel Effect, by changing the gate length ONLY. Perform the simulations in both linear and saturation regions, and then plot the threshold voltage values vs. gate length. Refer to Lecture 22, Slide 12. Lastly, you should run the last SDevice component, to generate the Ids vs. Vds curves under 4 Vgs values. Then take a look at the I-V curves to decide whether your device performance is limited by the “pinch-off” or the carrier velocity saturation. How to determine this? Refer to Lecture 22 Slide 10

Q&A Please - come to Dr. Xu’s office hours (Mon 12-1PM & Tue 3-4PM) OR - send him emails (nuoxu@eecs.berkeley.edu) OR - Post a question note on Piazza for any technical issues/problems.