twin well cmos fabrication steps using Synopsys TCAD

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step wise fabrication of twin well cmos

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twin well cmos fabrication steps using Synopsys TCAD

  1. 1. Rajesh Yadav 12ECP01P Aakansha 13VLP001 Surbhi 13VLP013 6/23/2014 1itm University, Gurgaon
  2. 2. Agenda Introduction Problem Statements Dimensioning using Mosis Design Rule Mask Designing Design steps using Synopsis TCAD Conclusion and Future Scopes References 6/23/2014 2itm University, Gurgaon
  3. 3. Agenda Introduction Problem Statements Dimensioning using Mosis Design Rule Mask Designing Design steps using Synopsis TCAD Conclusion and Future Scopes References 6/23/2014 3itm University, Gurgaon
  4. 4. Introduction • CMOS Design has basically Three Types • pwell CMOS • nwell CMOS • Twin well/ Twin Tub CMOS  Technology CAD is  Numeric simulation of Semiconductor Process and Device  Basic subprogram used in TCAD i. Sentaurus Structure Editor ii. Sentaurus Process iii. Sentaurus Device iv. Sentaurus Workbench v. Svisual . 6/23/2014 4itm University, Gurgaon
  5. 5. Agenda Introduction Problem Statements Dimensioning using Mosis Design Rule Mask Designing Design steps using Synopsis TCAD Conclusion and Future Scopes References 6/23/2014 5itm University, Gurgaon
  6. 6. Problem Statements • Using TCAD, Design a process sequence to fabricate the following CMOS structure This Design Involves the following unit steps 6/23/2014 6itm University, Gurgaon
  7. 7. Problem Statements 1. Silicon Substrate 2. n-well creation 3. P-well creation 4. Channel stop implant and FOX creation 5. Gate oxidation 6. Polysilicon deposition 7. nmos LDD Implant 8. pmos LDD implant 9. Spacer formation 10. nmos S-D Implantation 11. pmos S-D Implantation 12. Silicide formation 13. Oxide layer deposition 14. Aluminum Contacts n-well p/n type Silicon Substrate p-well 6/23/2014 7itm University, Gurgaon
  8. 8. Agenda Introduction Problem Statements Dimensioning using Mosis Design Rule Mask Designing Design steps using Synopsis TCAD Conclusion and Future Scopes References 6/23/2014 8itm University, Gurgaon
  9. 9. Dimensioning using Mosis Design Rule 6 4 2 4 6 2 1 1 3 3 2 2 2 24 n-mos/ p-mos Design Rule o Only in Y-direction(horizontal) dimension o All dimensions are in Lambda o 1Lambda = 100nm (for this particular Design, since channel length = 200nm) 6/23/2014 9itm University, Gurgaon
  10. 10. • Complete CMOS Dimensioning 6 4 44 6 6 4 44 6 18 Dimensioning using Mosis Design Rule Total substrate length required = 24+18+24 = 66λ 6/23/2014 10itm University, Gurgaon
  11. 11. Agenda Introduction Problem Statements Dimensioning using Mosis Design Rule Mask Designing Design steps using Synopsis TCAD Conclusion and Future Scopes References 6/23/2014 11itm University, Gurgaon
  12. 12. Mask Designing Mask-1: For nwell doping Mask-2: For pwell doping 42 24 4224 Mask-3: Active area (negative) Nitride etching Mask-4: Gate area (negative) Polysilicon etching 6 12 30 12 6 11 2 40 2 11 Mask-5: Sorce – Drain Region (negative) Gate-oxide etching Mask-6: for Titanium etching (negative) Mask-7: for contact cut in thick oxide (negative) 6 5 2 5 30 5 2 5 6 6 4 1214 30 41214 6 7 2 6 2 32 2 6 2 76/23/2014 12itm University, Gurgaon
  13. 13. Mask Designing Mask-8: Aluminum etching 6 3 6 3 30 3 63 6 For a good design steps, The number of mask required should be minimum 6/23/2014 13itm University, Gurgaon
  14. 14. Agenda Introduction Problem Statements Dimensioning using Mosis Design Rule Mask Designing Design steps using Synopsis TCAD Conclusion and Future Scopes References 6/23/2014 14itm University, Gurgaon
  15. 15. Design Steps Using Synopsys TCAD Step-1: Defining initial Substrate Step:2: Masking for nwell doping Length = 66Lambda =6.6 micron Depth = 1.5 micron Initial doping = 10E+14/cm3 with Boron Photomask-1 of thikness = 0.8 um. 6/23/2014 15itm University, Gurgaon
  16. 16. Step-3 : nwell doping with Phosphorus implantation Step-4 : Etching Mask-1 Design Steps Using Synopsys TCAD implant phosphorus dose=1.7e+10 energy=70 implant phosphorus dose=1.7e+10 energy=140 implant phosphorus dose=1.7e+10 energy=210 Required concentration = 1E+15/cm3 Required Depth of Implantation = 500nm 6/23/2014 16itm University, Gurgaon
  17. 17. Step-5 : Masking for pwell doping, Mask-2 Step-6 : pwell doping with Boron implantation Design Steps Using Synopsys TCAD Required concentration = 1E+15/cm3 Required depth = 500nm implant Boron dose=1.7e+10 energy=40 implant Boron dose=1.7e+10 energy=80 implant Boron dose=1.7e+10 energy=110 6/23/2014 17itm University, Gurgaon
  18. 18. Step-7 : Etching the photo Mask-2 Step-8 : Grow pad oxide Design Steps Using Synopsys TCAD 6/23/2014 18itm University, Gurgaon
  19. 19. Step-9 : Nitride deposition Step-10 : Patterning and etching Nitride using mask -3 (active area defination) Design Steps Using Synopsys TCAD 6/23/2014 19itm University, Gurgaon
  20. 20. Step-11 : Etching pad Oxide using, Mask-3 Step-12 : Masking for channel stop implant in pwell using Mask-2 Design Steps Using Synopsys TCAD 6/23/2014 20itm University, Gurgaon
  21. 21. Step-13 : Channel stop implant in pwell with Boron Step-14 : Etching Photomask-2 Design Steps Using Synopsys TCAD 6/23/2014 21itm University, Gurgaon
  22. 22. Step-15 : Masking for nwell channel stop implant with mask-1 Step-16 : nwell channel stop implant with Phosphorous Design Steps Using Synopsys TCAD 6/23/2014 22itm University, Gurgaon
  23. 23. Step-17 : Etching of photomask-1 Step-18 : Growing field oxide (Birds-Beak Formation) Design Steps Using Synopsys TCAD 6/23/2014 23itm University, Gurgaon
  24. 24. Step-19 : Etching Nitride Layer Step-20 : Growing Gate oxide Design Steps Using Synopsys TCAD 6/23/2014 24itm University, Gurgaon
  25. 25. Step-21 : Deposit Polysilicon Step-22 : selective etching of polysilicon using Mask-4 Design Steps Using Synopsys TCAD 6/23/2014 25itm University, Gurgaon
  26. 26. Step-23 : selective Etching of Gate Oxide using Mask-5 Step-24 : Masking for pmos LDD implant using mask-1 Design Steps Using Synopsys TCAD 6/23/2014 26itm University, Gurgaon
  27. 27. Step-25 : LDD Implantation for pmos with Boron Step-26 : Remove the Photomask-1 Design Steps Using Synopsys TCAD Desired Concentration = 1E+16/cm3 Desired Depth of Implantation = 30nm implant boron dose=3e+10 energy=3 6/23/2014 27itm University, Gurgaon
  28. 28. Step-27 : Masking for LDD Implant in nmos Step-28 : LDD Implantation in nmos with Phosphorous Design Steps Using Synopsys TCAD 6/23/2014 28itm University, Gurgaon
  29. 29. Step-29 : Etch photomask-2 Step-30 : Deposit Nitride Spacer Design Steps Using Synopsys TCAD 6/23/2014 29itm University, Gurgaon
  30. 30. Step-31 : Masking for Source – Drain implant in nmos using photomask-2 Step-32 : Source- Drain Implant in nmos with Phosphorous Design Steps Using Synopsys TCAD Desired Concentration = 1E+17/cm3 Desired Depth of implantation= 120nm implant phosphorus dose=1.2e+12 energy=25 6/23/2014 30itm University, Gurgaon
  31. 31. Step-33 : Etch photomask -2 Step-34 : Masking for pmos Source-Drain Implant using photomask-1 Design Steps Using Synopsys TCAD 6/23/2014 31itm University, Gurgaon
  32. 32. Step-35 : source-Drain Implantation of pmos using Boron Step-36 : Etching photomask-1 Design Steps Using Synopsys TCAD 6/23/2014 32itm University, Gurgaon
  33. 33. Step-37 : Titanium Silicide formation Step-38 : Selected etching of Titanium Design Steps Using Synopsys TCAD 6/23/2014 33itm University, Gurgaon
  34. 34. Step-39 : Thick Oxide layer deposition Step-40 : Selected Etching of thick Oxide layer Design Steps Using Synopsys TCAD 6/23/2014 34itm University, Gurgaon
  35. 35. Step-43 : Deposition of Contact aluminum layer Step-44 : Selected etching of Aluminum layer Design Steps Using Synopsys TCAD Done 6/23/2014 35itm University, Gurgaon
  36. 36. Agenda Introduction Problem Statements Dimensioning using Mosis Design Rule Mask Designing Design steps using Synopsis TCAD Conclusion and Future Scopes References 6/23/2014 36itm University, Gurgaon
  37. 37. Conclusion and future scope • Taken a substrate first as per our required dimension and lightly doped with Boron • nwell and pwell creation • Channel stop implantation and grown Field Oxide • Gate Oxide and Polysilicon layer deposition • LDD implantation • Spacer formation • Source – Drain Implantation • Silicide formation • Thick Oxide layer deposition for passivation • Selected etching of Thick oxide and deposition of Aluminum and patterning  Further characterization of the modeled device can be done using Sdevice.  Complete optimization of device can only be done after creating a device file (.des) correcponding to device characterization6/23/2014 37itm University, Gurgaon
  38. 38. Agenda Introduction Problem Statements Dimensioning using Mosis Design Rule Mask Designing Design steps using Synopsis TCAD Conclusion and Future Scopes References 6/23/2014 38itm University, Gurgaon
  39. 39. Refrences [1] Michael Duane, “The Role of TCAD in Compact Modelling ” , 3320 Scott Blvd.,MS 1148,Santa Clara,CA. [2] Sentaurus tool User Guide https://solvnet.synopsys.com.. 6/23/2014 39itm University, Gurgaon
  40. 40. 6/23/2014 40itm University, Gurgaon
  41. 41. THANK YOU 6/23/2014 41itm University, Gurgaon

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