Rui Huang Associate Professor Aerospace Engineering and Engineering Mechanics University of Texas at Austin Email: ruihuang@mail.utexas.edu Phone: 1-512-471-7558

1. Reliability in Advanced Interconnects and Packaging
2. Nonlinear Mechanics of Graphene and Carbon Nanotubes
3. Buckling of Nanostructures
4. Wrinkling of Thin Films on Soft Substrates
5. Surface Morphological Evolution and Self-Assembly of Quantum Dots
6. Stress Relaxation and Interface Diffusion in Copper Interconnects
7. Fracture in Thin-Film Structures
8. Strain-Relaxed SiGe Islands on Oxides
9. Deformation Mechanisms in Metallic Glasses
10. Theory and Applications of Mechanical Resonators

Reliability in Advanced Interconnects and Packaging

Collaborators: Kenneth M. Liechti (UT Austin), Paul S. Ho (UT Austin), Michael Lane (Emory & Henry College)
Funding: Semiconductor Research Cooperation (SRC) and Tokyo Electron

Presentation slides:

• Stress Analyses and Mechanical Reliability of 3D Interconnects with Through-Silicon Vias, International Workshop on 3D Design and Nanoelectronic System Technologies, Georgia Institute of Technology, Atlanta, GA, June 15, 2009.

Publications:

• X. Zhang, S.-K. Ryu, R. Huang, P.S. Ho, J. Liu, D. Toma, Mechanical stability of air-gap interconnects. Future Fab 27, 81-87 (October 2008).
• X. Zhang, S. H. Im, R. Huang, P. S. Ho, Chip-Packaging Interaction and Reliability Impact on Cu/Low-k Interconnects. Chapter 2, Integrated Interconnect Technologies for 3D Nanoelectronic Systems (Editors: M. Bakir and J. Meindl), Artech House, Norwood, MA, 2008.

Nonlinear Mechanics of Graphene and Carbon Nanotubes

Collaborators: Marino Arroyo (Spain)
Funding: NSF

Presentation slides:

• Nonlinear Mechanics of Graphene Monolayer, Texas A&M University, November 19, 2009

Publications:

• Q. Lu and R. Huang, Nonlinear mechanics of single-atomic-layer graphene sheets. Int. J. Applied Mechanics 1, 443-467 (2009).
• Q. Lu, M. Arroyo, R. Huang, Elastic bending modulus of monolayer graphene. J. Phys. D: Appl. Phys. 42, 102002 (2009). Posted online at arXiv:0901.4370v1.
• J. Zhou and R. Huang, Internal lattice relaxation of single-layer graphene under in-plane deformation. Journal of the Mechanics and Physics of Solids 56, 1609-1623 (2008).

Buckling of Nanostructures

Collaborators: Paul S. Ho (UT-Austin)
Funding: National Science Foundation

Publications:

• B. Li, Q. Zhao, H. Huang, Z. Luo, M.K. Kang, J.-H. Im, R. Allen, M.W. Cresswel, R. Huang, and P.S Ho, Indentation of Single-Crystal Silicon Nanolines: Buckling and Contact Friction at Nanoscales. J. Applied Physics 105, 073510 (2009).
• B. Li, H. Huang, Q. Zhao, Z. Luo, J.-H. Im, P.S Ho, M.K. Kang, R. Huang, and M.W. Cresswel, Mechanical Characterization of High Aspect Ratio Silicon Nanolines. In: Mechanics of Nanoscale Materials, edited by C. Friesen, R.C. Cammarata, A. Hodge, O.L. Warren (Mater. Res. Soc. Symp. Proc., vol. 1086E, Warrendale, PA, 2008), 1086-U05-07.
• M. K. Kang, B. Li, P.S. Ho, R. Huang, Buckling of Single-Crystal Silicon Nanolines under Indentation. Journal of Nanomaterials, Vol. 2008, Article ID 132728 (11 pages), April 2008. DOI: 10.1155/2008/132728.
• B. Li, M. K. Kang, K. Lu, R. Huang, P. S. Ho, R. A. Allen, and M. W. Cresswell, Fabrication and Characterization of Patterned Single-Crystal Silicon Nanolines. Nano Letters 8, 92 -98 (2008).

Wrinkling of Thin Films on Soft Substrates

Collaborators: C.M. Stafford (NIST), Z. Suo (Harvard Univ.)
Funding: National Science Foundation and DARPA

Presentation slides:

• Nonlinear Dynamics of Wrinkle Growth and Pattern Formation in Stressed Elastic Thin Films, APS March Meeting, Pittsburgh, March 18, 2009.

Publications:

• E.P. Chan, K.A. Page, S.H. Im, D.L. Patton, R. Huang, C.M. Stafford, Viscoelastic properties of confined polymer films measured via thermal wrinkling. Soft Matter 5, 4638-4641 (2009).
• S. H. Im and R. Huang, Wrinkle Patterns of Anisotropic Crystal Films on Viscoelastic Substrates. J. Mech. Phys. Solids 56, 3315-3330 (2008). doi: 10.1016/j.jmps.2008.09.011.
• H. Mei, J.Y. Chung, H.-H. Yu, C.M. Stafford, and R. Huang, Buckling modes of elastic thin films on elastic substrates. Applied Physics Letters 90, 151902 (2007).
• R. Huang, C.M. Stafford, B.D. Vogt, Wrinkling of ultrathin polymer films. In: Mechanics of Nanoscale Materials and Devices, edited by A. Misra, J.P. Sullivan, H. Huang, K. Lu, and S. Asif (Mater. Res. Soc. Symp. Proc., vol. 924E, Warrendale, PA, 2006), 0924-Z04-10.
• R. Huang and S.H. Im, Dynamics of wrinkle growth and coarsening in stressed thin films. Physical Review E 74, 026214 (2006).
• R. Huang, C.M. Stafford, B.D. Vogt, Effect of surface properties on wrinkling of ultrathin films. J. Aerospace Engineering 20, 38-44 (2007).
• C.M. Stafford, B.D. Vogt, C. Harrison, D. Julthongpiput, R. Huang, Elastic Moduli of Ultrathin Amorphous Polymer Films. Macromolecules 39, 5095-5099 (2006).
• R. Huang, Electrically induced surface instability of a conductive thin film on a dielectric substrate. Applied Physics Letters 87, 151911 (2005).
• S.H. Im and R. Huang, Evolution of wrinkles in elastic-viscoelastic bilayer thin films. J. Applied Mechanics 72, 955-961 (2005).
• S.H. Im and R. Huang, Morphological instability and kinetics of an elastic film on a viscoelastic layer. Proceedings of IUTAM Symposium on Size Effects on Material and Structure Behavior at Micron- and Nano-Scales (Eds. Q.P. Sun and P. Tong, Hong Kong, 31 May - 4 June, 2004), Springer 2006, pp. 41-50.
• S.H. Im and R. Huang, Ratcheting-induced wrinkling of an elastic film on a metal layer under cyclic temperatures. Acta Mater 52, 3707-3719 (2004).
• R. Huang, Kinetic wrinkling of an elastic film on a viscoelastic substrate. Journal of the Mechanics and Physics of Solids 53, 63-89 (2005).
• R. Huang and Z. Suo, Very thin solid-on-liquid structures: the interplay of flexural rigidity, membrane force, and interfacial force. Thin Solid Films 429, 273-281 (2003).
• R. Huang, Z. Suo, Morphological instability of solid-on-liquid thin film structures. MRS Symposium Proceedings, vol. 749, 121-126 (2002).
• R. Huang and Z. Suo, Instability of a compressed elastic film on a viscous layer. International Journal of Solids and Structures 39, 1791-1802 (2002).
• R. Huang and Z. Suo, Wrinkling of a compressed elastic film on a viscous layer. Journal of Applied Physics 91, 1135-1142 (2002).

Surface Morphological Evolution and Self-Assembly of Quantum Dots

Collaborators: Sanjay Banerjee (UT Austin)
Funding: Department of Energy

Publications:

• Y. Pang and R. Huang, Effect of Elastic Anisotropy on Surface Pattern Evolution of Epitaxial Thin Films. Int. J. Solids and Structures 46, 2822-2833 (2009).
• Y. Pang and R. Huang, Bifurcation of Surface Pattern in Epitaxial Thin Films under Anisotropic Stresses. J. Applied Physics 101, 023519 (2007).
• Y. Pang and R. Huang, Pattern Evolution of Self-Assembled Quantum Dots Under Biaxial Stresses. In: Nanomanufacturing, edited by F. Stellacci, J.W. Perry, G.S. Herman, and R.N. Das (Mater. Res. Soc. Symp. Proc., vol. 921E, Warrendale, PA, 2006), 0921-T07-08.
• Y. Pang and R. Huang, Nonlinear effect of stress and wetting on surface evolution in epitaxial thin films. Physical Review B 74, 075413 (2006).
• H. Liu and R. Huang, Effect of a cap layer on morphological stability of a strained epitaxial film. J. Applied Physics 97, 113537 (2005).

Stress Relaxation and Interface Diffusion in Copper Interconnects

Collaborators: Paul S. Ho (UT Austin) and Jun He (Intel)
Funding: Advanced Technology Program of Texas Higher Education Coordinating Board and Intel Corporation

Publications:

• H. Mei, J.H. An, R. Huang, and P.J. Ferreira, Finite element modeling of stress variation in multilayer thin-film specimens for in-situ transmission electron microscopy experiments. Journal of Materials Research 22, 2737-2741 (2007).
• D.W. Gan, P.S. Ho, Y. Pang, R. Huang, J. Leu, J. Maiz, T. Scherban, Effect of passivation on stress relaxation in electroplated copper films. J. Materials Research 21, 1512-1518 (2006).
• D.W. Gan, R. Huang, P.S. Ho, J. Leu, J. Maiz, T. Scherban, Effects of passivation layer on stress relaxation and mass transport in electroplated Cu films. Proceedings of the 7th International Workshop on Stress-Induced Phenomena in Metallization, Austin, Texas, 14-16 June 2004. AIP Conference Proceedings 741, 256-267 (2004).
• R. Huang, D.W. Gan, P.S. Ho, Isothermal stress relaxation in electroplated Cu films. Part II: Kinetic modeling. J. Applied Physics 97, 103532 (2005).
• D.W. Gan, R. Huang, P.S. Ho, J. Leu, J. Maiz, T. Scherban, Isothermal stress relaxation in electroplated Cu films. Part I: Mass transport measurements. J. Applied Physics 97, 103531 (2005).

Fracture in Thin-Film Structures

Collaborators: Z. Suo (Harvard Univ.), J.H. Prevost (Princeton Univ.)
Funding: National Science Foundation

Presentation slides:

• Fracture of Brittle Thin Films on Compliant Substrates, 12th International Conference on Fracture, Ottawa, Canada, July 16, 2009.

Publications:

• H. Mei, Y. Pang, and R. Huang, Influence of interfacial delamination on channel cracking of elastic thin films. International Journal of Fracture 148, 331-342 (2007).
• Y. Pang and R. Huang, Influence of interfacial delamination on channel cracking of brittle thin films. In: Materials, Processes, Integration and Reliability in Advanced Interconnects for Micro- and Nanoelectronics, edited by Q. Lin, E.T. Ryan, W-L. Wu, D.Y. Yoon (Mater. Res. Soc. Symp. Proc. Vol. 990, Warrendale, PA), B06-04, 2007.
• J. Liang, R. Huang, J.H. Prevost, and Z. Suo, Thin film cracking modulated by underlayer creep. Experimental Mechanics, 43, 269-279 (2003).
• R. Huang, N. Sukumar, J.H. Prevost, Modeling quasi-static crack growth with the extended finite element method -Part II: Numerical Applications. International Journal of Solids and Structures 40, 7539-7552 (2003).
• R. Huang, J.H. Prevost, Z.Y. Huang, and Z. Suo, Channel-cracking of thin films with the extended finite element method. Engineering Fracture Mechanics 70, 2513-2526 (2003).
• J. Liang, R. Huang, J.H. Prevost, and Z. Suo, Evolving crack patterns in thin films with the extended finite element method. International Journal of Solids and Structures 40, 2343-2354 (2003).
• R. Huang, J.H. Prevost, and Z. Suo, Loss of constraint on fracture in thin film structures due to creep. Acta Materialia 50, 4137-4148 (2002).

Strain-Relaxed SiGe Islands on Oxides

Collaborators: Z. Suo, J.C. Sturm, K.D. Hobart, H. Yin
Funding: National Science Foundation and DARPA

Publications:

• H. Yin, R. Huang, K.D. Hobart, J. Liang, Z. Suo, S.R. Shieh, T.S. Duffy, F.J. Kub, J.C. Sturm, Buckling suppression of SiGe islands on compliant substrates. Journal of Applied Physics 94, 6875-6882 (2003).
• R. Huang and Z. Suo, Very thin solid-on-liquid structures: the interplay of flexural rigidity, membrane force, and interfacial force. Thin Solid Films 429, 273-281 (2003).
• R. Huang, Z. Suo, Morphological instability of solid-on-liquid thin film structures. MRS Symposium Proceedings, vol. 749, 121-126 (2002).
• R. Huang, H. Yin, J. Liang, J.C. Sturm, K.D. Hobart, Z. Suo, Mechanics of relaxing SiGe islands on a viscous glass. Acta Mechanica Sinica 18, 441-456 (2002).
• H. Yin, R. Huang, K.D. Hobart, Z. Suo, T.S. Kuan, C.K. Inoki, S.R. Shieh, T.S. Duffy, F.J. Kub, J.C. Sturm, Strain relaxation of SiGe islands on compliant oxide. Journal of Applied Physics 91, 9716-9722 (2002).
• J. Liang, R. Huang, H. Yin, J. C. Sturm, K. D. Hobart, and Z. Suo, Relaxation of compressed elastic islands on a viscous layer. Acta Materialia 50, 2933-2944 (2002).
• R. Huang and Z. Suo, Instability of a compressed elastic film on a viscous layer. International Journal of Solids and Structures 39, 1791-1802 (2002).
• R. Huang and Z. Suo, Wrinkling of a compressed elastic film on a viscous layer. Journal of Applied Physics 91, 1135-1142 (2002).
• R. Huang, H. Yin, J. Liang, K. D. Hobart, J. C. Sturm, and Z. Suo, Relaxation of a strained elastic film on a viscous layer. MRS Symposium Proceedings, vol. 695, 115-120 (2001).

Deformation Mechanisms in Metallic Glasses

Collaborators: Z. Suo, J.H. Prevost, W.D. Nix
Funding: National Science Foundation

Publications:

• R. Huang, Z. Suo, J.H. Prevost, and W.D. Nix, Inhomogeneous deformation in metallic glasses. Journal of the Mechanics and Physics of Solids 50, 1011-1027 (2002).

Theory and Applications of Mechanical Resonators

"Vibrations of Piezoelectric Crystal Plates with Thickness-Graded Material Properties", PhD thesis, Princeton University, January 2001.
Advisor: Peter C. Y. Lee
Collaborators: Jiun-Der Yu, Wen-Sen Lin, W.H. Shih, T. Knowles
Funding: U.S. Army Research Office

Publications:

• T. Knowles, M.K. Kang, R. Huang, Trapped torsional vibrations in elastic plates. Applied Physics Letters 87, 201911 (2005).
• M.K. Kang, R. Huang, T. Knowles, Torsional vibrations of circular elastic plates with thickness steps. IEEE Trans. Ultrasonics, Ferroelectrics and Frequency Control, vol. 53, 349-359 (2006).
• R. Huang, P.C.Y. Lee, W.S. Lin and J.D. Yu, Extensional, thickness-stretch, and symmetric thickness-shear vibrations of piezoelectric ceramic disks. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 49, 1507-1515 (2002).
• P.C. Y. Lee and R. Huang, Mechanical effects of electrodes on the vibrations of quartz crystal plates. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 49, 612-625 (2002).
• P.C.Y. Lee and R. Huang, Effects of a liquid layer on thickness-shear vibrations of rectangular AT-cut quartz plates. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 49, 604-611 (2002).
• P.C.Y. Lee, R. Huang, X. Li, and W. H. Shih, Vibrations and static responses of asymmetric bimorph disks of piezoelectric ceramics. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 47, 706-715 (2000).