Measuring Surface Energies of GaAs (100) and Si (100) by Three Liquid Contact Angle Analysis (3LCAA) for Heterogeneous Nano-BondingTM

Christian E. Cornejo, Michelle E. Bertram, Timoteo C. Diaz, Saaketh R. Narayan, Sukesh Ram, Karen L. Kavanagh, Nicole Herbots, Jack M. Day, Franscesca J. Ark, Ajit Dhamdhere, Robert J. Culbertson, Rafiqul Islam

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Analysis of the total surface energy γT and its three components as established by the van Oss-Chaudhury-Good Theory (vOCG) is conducted via Three Liquid Contact Angle Analysis (3LCAA). γT is correlated with the composition of the top monolayers (ML) obtained from High-Resolution Ion Beam Analysis (HR-IBA). Control of γT enables surface engineering for wafer bonding (Nano-BondingTM) and/or epitaxial growth. Native oxides on boron-doped p-Si(100) are found to average γT of 53 ± 1.4 mJ/m2) and are always hydrophilic. An HF in methanol or aqueous HF etch for 60 s always renders Si(100) hydrophobic. Its γT decreases by 20% to 44 ± 3 mJ/m2 in HF in methanol etch and by 10% to 48 ± 3 mJ/m2 in aqueous HF. On the contrary, GaAs(100) native oxides are found to always be hydrophobic. Tellurium n+-doped GaAs(100) yields an average of γT of 37 ± 2 mJ/m2, 96% of which is due to the Lifshitz-Van der Waals molecular interactions (γLW = 36 ± 1 mJ/m2). However, hydrophobic GaAs(100) can be made highly hydrophilic. After etching, γT increases by almost 50% to 66 ± 1.4 mJ/m2. 3LCAA shows that the γT increase is due to electron acceptor and donor interactions, while the Lifshitz-van der Waals energy γLW remains constant. IBA combining the 3.039 ± 0.01 MeV oxygen nuclear resonance with <111> channeling, shows that oxygen on Si(100) decreases by 10% after aqueous HF etching, from 13.3 ± 0.3 monolayers (ML) to 11.8 ± 0.4 ML 1 hour after etch.Te-doped GaAs(100) exhibits consistent oxygen coverage of 7.2 ± 1.4 ML, decreasing by 50% after etching to a highly hydrophilic surface with 3.6 ± 0.2 oxygen ML. IBA shows that etching does not modify the GaAs surface stoichiometry to within 1%. Combining 3LCAA with HR-IBA provides a quantitative metrology to measure how GaAs and Si surfaces can be altered to a different hydroaffinity and surface termination.

Original languageEnglish (US)
Pages (from-to)3403-3411
Number of pages9
JournalMRS Advances
Issue number57-58
StatePublished - 2018
Externally publishedYes


  • III-V
  • Si
  • ion beam analysis
  • oxide
  • surface chemistry

ASJC Scopus subject areas

  • Mechanical Engineering
  • Mechanics of Materials
  • Materials Science(all)
  • Condensed Matter Physics


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