International Journal of Fracture

, Volume 216, Issue 2, pp 161–171 | Cite as

A fracture model for exfoliation of thin silicon films

  • Martin Ward
  • Michael CullinanEmail author
Original Paper


The direct exfoliation of thin films from silicon wafers has the potential to significantly lower the cost of flexible electronics while leveraging the performance benefits and established infrastructure of traditional wafer-based fabrication processes. However, controlling the thickness and uniformity of exfoliated silicon thin films has proven difficult due to a lack of understanding and control over the exfoliation process. This paper presents a new silicon exfoliation process and model which enables accurate prediction of the thickness and quality of the exfoliated thin-film based on the exfoliation process parameters. This model uses a parametric, finite element, linear elastic fracture mechanics study with nonlinear loading to determine how each process parameter affects the crack propagation depth. A metamodel is then constructed from the results of numerous simulations to inform the design and operation of a novel exfoliation tool and predict thickness of produced films. In order to manufacture uniform, high-quality films, the tool creates a controlled peeling load that is able to propagate a crack through the silicon in a controlled manner. Finally, exfoliated silicon samples produced with the prototype tool are evaluated and compared to metamodel projections, confirming the ability of the tool to steer crack trajectory within ± 3 microns of the crack depth predictions.


Exfoliation Single crystal silicon Finite element analysis Spalling 



The authors acknowledge and thank Miaomiao Yang for her experience, effort, insight, and support in accomplishing this work. The authors thank Kirsten Cole Christopherson for her effort in completing these experiments. The authors would also like to thank Liam Conolly, Dipankar Behera, and Cheng Zhao for the informative discussions and technical expertise. This work is based upon work supported primarily by the National Science Foundation under Cooperative Agreement No. EEC-1160494. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.


  1. Ahn J, Chou H, Banerjee SK (2017) Graphene-Al\(_{2}\)O\(_{3}\)-silicon heterojunction solar cells on flexible silicon substrates. J Appl Phys 121(16):163105. CrossRefGoogle Scholar
  2. Bedell SW, Shahrjerdi D, Hekmatshoar B, Fogel K, Lauro PA, Ott JA, Sosa N, Sadana D (2012) Kerf–Less removal of Si, Ge, and III–V layers by controlled spalling to enable low-cost PV technologies. IEEE J Photovolt 2(2):141–147. CrossRefGoogle Scholar
  3. Bedell SW, Fogel K, Lauro P, Shahrjerdi D, Ott JA, Sadana D (2013a) Layer transfer by controlled spalling. J Phys D Appl Phys 46(15):152002. CrossRefGoogle Scholar
  4. Bedell SW, Shahrjerdi D, Fogel K, Lauro P, Hekmatshoar B, Li N, Ott J, Sadana DK (2013b) (Invited) cost-effective layer transfer by controlled spalling technology. ECS Trans 50(7):315–323. CrossRefGoogle Scholar
  5. Bouchard PO, Bernacki M, Parks D (2013) Analysis of stress intensity factors and T-stress to control crack propagation for kerf-less spalling of single crystal silicon foils. Comput Mater Sci 69:243–250. CrossRefGoogle Scholar
  6. Calvez D, Roqueta F, Jacques S, Bechou L, Ousten Y, Ducret S (2014) Crack propagation modeling in silicon: a comprehensive thermomechanical finite-element model approach for power devices. IEEE Trans Compon Packag Manuf Technol 4(2):360–366. CrossRefGoogle Scholar
  7. Cannon RM, Fisher RM, Evans AG (1985) Decohesion of thin films from ceramic substrates. In: MRS proceedings, vol 54.
  8. Drory MD, Thouless MD, Evans AG (1988) On the decohesion of residually stressed thin films. Acta Metall 36(8):2019–2028CrossRefGoogle Scholar
  9. Dross F, Robbelein J, Vandevelde B, Van Kerschaver E, Gordon I, Beaucarne G, Poortmans J (2007) Stress-induced large-area lift-off of crystalline Si films. Appl Phys A 89(1):149–152. CrossRefGoogle Scholar
  10. Fortunato E, Barquinha P, Martins R (2012) Oxide semiconductor thin-film transistors: a review of recent advances. Adv Mater 24(22):2945–2986. CrossRefGoogle Scholar
  11. Janssen G, Abdalla M, van Keulen F, Pujada B, van Venrooy B (2009) Celebrating the 100th anniversary of the Stoney equation for film stress: developments from polycrystalline steel strips to single crystal silicon wafers. Thin Solid Films 517(6):1858–1867. CrossRefGoogle Scholar
  12. Kim J, Lee M, Shim HJ, Ghaffari R, Cho HR, Son D, Jung YH, Soh M, Choi C, Jung S, Chu K, Jeon D, Lee ST, Kim JH, Choi SH, Hyeon T, Kim DH (2014) Stretchable silicon nanoribbon electronics for skin prosthesis. Nat Commun 5:5747. CrossRefGoogle Scholar
  13. Luo J (2004) Young’s modulus of electroplated Ni thin film for MEMS applications. Mater Lett 58(17–18):2306–2309. CrossRefGoogle Scholar
  14. Masolin A, Bouchard PO, Martini R, Bernacki M (2013) Thermo-mechanical and fracture properties in single-crystal silicon. J Mater Sci 48(3):979–988. CrossRefGoogle Scholar
  15. Mathew L, Jawarani D (2010) Method of forming an electronic device using a separation-enhancing species. US patent US7749884B2.
  16. Pagliaro M, Ciriminna R, Palmisano G (2008) Flexible solar cells. ChemSusChem 1(11):880–891. CrossRefGoogle Scholar
  17. Pang C, Lee C, Suh KY (2013) Recent advances in flexible sensors for wearable and implantable devices. J Appl Polym Sci 130(3):1429–1441. CrossRefGoogle Scholar
  18. Pudasaini PR, Sharma M, Ruiz-Zepeda F, Ayon AA (2014) Ultrathin, flexible, hybrid solar cells in sub-ten micrometers single crystal silicon membrane. In: 2014 IEEE 40th photovoltaic specialist conference (PVSC). IEEE, pp 0953–0955Google Scholar
  19. Rao RA, Mathew L, Saha S, Smith S, Sarkar D, Garcia R, Stout R, Gurmu A, Onyegam E, Ahn D (2011) A novel low cost 25\(\mu \)m thin exfoliated monocrystalline si solar cell technology. In: 2011 37th IEEE photovoltaic specialists conference (PVSC). IEEE, pp 001504–001507Google Scholar
  20. Shahrjerdi D, Bedell SW (2013) Extremely flexible nanoscale ultrathin body silicon integrated circuits on plastic. Nano Lett 13(1):315–320. CrossRefGoogle Scholar
  21. Shahrjerdi D, Bedell SW, Khakifirooz A, Fogel K, Lauro P, Cheng K, Ott JA, Gaynes M, Sadana DK (2012) Advanced flexible CMOS integrated circuits on plastic enabled by controlled spalling technology. In: 2012 IEEE international electron devices meeting (IEDM). IEEE, pp 5–1Google Scholar
  22. Suo Z, Hutchinson JW (1989) Steady-state cracking in brittle substrates beneath adherent films. Int J Solids Struct 25(11):1337–1353. CrossRefGoogle Scholar
  23. Takei K, Takahashi T, Ho JC, Ko H, Gillies AG, Leu PW, Fearing RS, Javey A (2010) Nanowire active-matrix circuitry for low-voltage macroscale artificial skin. Nat Mater 9:821–826.
  24. Tanielian M, Lajos RE, Blackstone S (1986) Method of making thin free standing single crystal films US patent US4582559A.
  25. Thouless MD, Evans AG, Ashby MF, Hutchinson JW (1987) The edge cracking and spalling of brittle plates. Acta Metall 35(6):1333–1341. CrossRefGoogle Scholar
  26. Weil R (1970) The origins of stress in electrodeposits. Part 1. Plating 57(12):1231–1237Google Scholar
  27. Xu Y, Blume JA, Shih CF (1993) An interface crack between an orthotropic thin film and substrate. Int J Fract 63(4):369–381CrossRefGoogle Scholar
  28. Ying M, Bonifas AP, Lu N, Su Y, Li R, Cheng H, Ameen A, Huang Y, Rogers JA (2012) Silicon nanomembranes for fingertip electronics. Nanotechnology 23(34):344004. CrossRefGoogle Scholar
  29. Zhai Y, Mathew L, Rao R, Xu D, Banerjee SK (2012) High-performance flexible thin-film transistors exfoliated from bulk wafer. Nano Lett 12(11):5609–5615. CrossRefGoogle Scholar

Copyright information

© Springer Nature B.V. 2019

Authors and Affiliations

  1. 1.Department of Mechanical EngineeringUniversity of Texas at AustinAustinUSA

Personalised recommendations