Hostname: page-component-7d684dbfc8-w65q4 Total loading time: 0 Render date: 2023-09-23T19:15:05.275Z Has data issue: false Feature Flags: { "corePageComponentGetUserInfoFromSharedSession": true, "coreDisableEcommerce": false, "coreDisableSocialShare": false, "coreDisableEcommerceForArticlePurchase": false, "coreDisableEcommerceForBookPurchase": false, "coreDisableEcommerceForElementPurchase": false, "coreUseNewShare": true, "useRatesEcommerce": true } hasContentIssue false

Structure of vapor-phase deposited Al-Ge thin films and Al-Ge intermediate layer bonding of Al-based microchannel structures

Published online by Cambridge University Press:  31 January 2011

W.J. Meng*
Department of Mechanical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803
D.J. Miller
Electron Microscopy Center and Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439
a) Address all correspondence to this author. e-mail:
Get access


Al-based high-aspect-ratio microscale structures (HARMS) are basic building blocks for all-Al microdevices. Bonding of Al-based HARMS is essential for device assembly. In this paper, bonding of Al-based HARMS to flat Al plates using Al-Ge thin film intermediate layers is investigated. The structure of sputter codeposited Al-Ge thin films was studied by high-resolution transmission electron microscopy as a function of the average film composition. The structure of the interface region between Al-based HARMS bonded to flat Al plates is studied by combining focused ion beam sectioning and scanning electron microscopy. An extended bonding interface region, ∼100 μm in width, is observed and suggested to result from liquidus/solidus reactions as well as diffusion of Ge in solid Al at the bonding temperature of 500 °C. The extended interface region is suggested to be beneficial to Al-Al bonding via Al-Ge intermediate layers.

Copyright © Materials Research Society 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)



1.Tanaka, M.: An industrial and applied review of new MEMS devices features. Microelectron. Eng. 84, (5-8)1341 (2007)CrossRefGoogle Scholar
2.Miki, N.: Wafer bonding techniques for MEMS. Sensor Letters 3, (4)263 (2005)CrossRefGoogle Scholar
3.Christiansen, S.H., Singh, R., Gosele, U.: Wafer direct bonding: From advanced substrate engineering to future applications in micro/nano electronics. IEEE Proc. 94, (12)2060 (2006)CrossRefGoogle Scholar
4.Knowles, K.M., van Helvoort, A.T.J.: Anodic bonding. Int. Mater. Rev. 51, (5)273 (2006)CrossRefGoogle Scholar
5.Gerlach, A., Maas, D., Seidel, D., Bartuch, H., Schundau, S., Kaschlik, K.: Low-temperature anodic bonding of silicon to silicon wafers by means of intermediate glass layers. Microsyst. Technol. 5, (3)144 (1999)CrossRefGoogle Scholar
6.Takagi, H., Kikuchi, K., Maeda, R., Chung, T.R., Suga, T.: Surface activated bonding of silicon wafers at room temperature. Appl. Phys. Lett. 68, (16)2222 (1996)CrossRefGoogle Scholar
7.Gabriel, M., Johnson, B., Suss, R., Reiche, M., Eichler, M.: Wafer direct bonding with ambient pressure plasma activation. Microsyst. Technol. 12, (5)397 (2006)CrossRefGoogle Scholar
8.Kelly, G., Morrissey, A., Alderman, J., Camon, H.: 3-D packaging methodologies for microsystems. IEEE Trans. Adv. Packag. 23, (4)623 (2000)Google Scholar
9.Williams, J.D., Wang, W.: Microfabrication of an electromagnetic power relay using SU-8 based UV-LIGA technology. Microsyst. Technol. 10, (10)699 (2004)CrossRefGoogle Scholar
10.Mei, F., Parida, P.R., Jiang, J., Meng, W.J., Ekkad, S.V.: Fabrication, assembly, and testing of Cu- and Al- based microchannel heat exchangers. J. Microelectromech. Syst. 17, (4)869 (2008)Google Scholar
11.Madou, M.: Fundamentals of Microfabrication(CRC Press Boca Raton, FL 2000)Google Scholar
12.Bhushan, A., Yemane, D., Overton, E.B., Goettert, J., Murphy, M.C.: Fabrication and preliminary results for LiGA fabricated nickel micro gas chromatograph columns. J. Microelectromech. Syst. 16, (2)383 (2007)CrossRefGoogle Scholar
13.Cao, D.M., Meng, W.J., Kelly, K.W.: High-temperature instrumented microscale compression molding of Pb. Microsyst. Technol. 10, 323 (2004)CrossRefGoogle Scholar
14.Cao, D.M., Meng, W.J.: Microscale compression molding of Al with surface engineered LiGA inserts. Microsyst. Technol. 10, 662 (2004)CrossRefGoogle Scholar
15.Jiang, J., Mei, F., Meng, W.J., Lara-Curzio, E.: Microscale molding replication of Cu- and Ni-based structures. Microsyst. Technol. 14, 1731 (2008)CrossRefGoogle Scholar
16.Lancaster, J.F.: Metallurgy of Welding(Chapman and Hall London 1993)Google Scholar
17.Tiensuu, A.L., Bexell, M., Schweitz, J.A., Smith, L., Johansson, S.: Assembling three-dimensional microstructures using gold-silicon eutectic bonding. Sens. Actuators, A 45, 227 (1994)CrossRefGoogle Scholar
18.Massalski, T.B.: Binary Alloy Phase Diagrams(ASM, Metals Park OH 1986)116Google Scholar
19.Vu, B., Zavracky, P.M.: Patterned eutectic bonding with Al/Ge thin films for microelectromechanical systems. J. Vac. Sci. Technol. B 14, (4)2588 (1996)CrossRefGoogle Scholar
20.Mei, F., Jiang, J., Meng, W.J.: Eutectic bonding of Al-based high aspect ratio microscale structures. Microsyst. Technol. 13, 723 (2007)CrossRefGoogle Scholar
21.Mei, F., Jiang, J., Meng, W.J.: Evaluation of eutectic bond strength and assembly of Al-based microfluidic structures. Microsyst. Technol. 14, 99 (2007)CrossRefGoogle Scholar
22.Adams, C.D., Atzmon, M., Cheng, Y.T., Srolovitz, D.J.: Phase-separation during codeposition of Al-Ge thin-films. J. Mater. Res. 7, (3)653 (1992)CrossRefGoogle Scholar
23.Meng, W.J., Curtis, T.J., Rehn, L.E., Baldo, P.M.: Temperature dependence of inductively coupled plasma assisted deposition of titanium nitride coatings. Surf. Coat. Technol. 120/121, 206 (1999)CrossRefGoogle Scholar
24.Meng, W.J., Meletis, E.I., Rehn, L.E., Baldo, P.M.: Inductively-coupled plasma assisted deposition and mechanical properties of metal-free and Ti-containing hydrocarbon coatings. J. Appl. Phys. 87, 2840 (2000)CrossRefGoogle Scholar
25.Shi, B., Meng, W.J., Rehn, L.E., Baldo, P.M.: Intrinsic stress development in Ti-C:H ceramic nanocomposite coatings. Appl. Phys. Lett. 81, 352 (2002)CrossRefGoogle Scholar
26.Adams, C.D., Atzmon, M., Cheng, Y.T., Srolovitz, D.J.: Transition from lateral to transverse phase-separation during film codeposition. Appl. Phys. Lett. 59, (20)2535 (1991)CrossRefGoogle Scholar
27.Unruh, K.M., Chien, C.L.: Magnetic properties and hyperfine interactions in amorphous Fe-Zr alloys. Phys. Rev. B: Condens. Matter. 30, (9)4968 (1984)CrossRefGoogle Scholar
28.Hertzberg, R.W.: Deformation and Fracture Mechanics of Engineering Materials(Wiley New York 1996)Google Scholar
29.Lau, S.S., van der Weg, W.F.: Solid phase epitaxyThin Films—Interdiffusion and Reactions edited by J.M. Poate, K.N. Tu, and J.W. Mayer (Wiley New York 1978)Google Scholar
30.Thurer, A., Rummel, G., Zumkley, T., Freitag, K., Mehrer, H.: Temperature and pressure dependence of Ge diffusion in aluminum. Phys. Status Solidi A 149, 535 (1995)CrossRefGoogle Scholar
31.Raghavan, G., Rao, G.V., Amarendra, G., Tyagi, A.K., Viswanathan, B.: Study of interdiffusion and defect evolution in thin film Al/Ge bilayers using SIMS and positron beam. Appl. Surf. Sci. 178, 75 (2001)CrossRefGoogle Scholar
32.Crank, J.: The Mathematics of Diffusion(Oxford University Press London 1975)Google Scholar
33.Kaneko, K., Inoke, K, Sato, K., Kitawaki, K., Higashida, H., Arslan, I., Midgley, P.A.: TEM characterization of Ge precipitates in an Al–1.6 at.% Ge alloy. Ultramicroscopy 108, 210 (2008)CrossRefGoogle Scholar