AVS 47th International Symposium
    Semiconductors Monday Sessions
       Session SC2+EL+SS-MoM

Paper SC2+EL+SS-MoM4
Techniques and Interface Effects in Creating Alternative Substrates using GaAs Wafer Bonding

Monday, October 2, 2000, 9:20 am, Room 312

Session: Dissimilar Materials
Presenter: A.M. Cain, Air Force Research Laboratory
Authors: A.M. Cain, Air Force Research Laboratory
P.J. Hesse, Air Force Research Laboratory
D.R. Thomas, Air Force Research Laboratory
K.G. Eyink, Air Force Research Laboratory
D.H. Tomich, Air Force Research Laboratory
M. Ruddell, Air Force Research Laboratory
T.W. Haas, Air Force Research Laboratory
M.L. Seaford, Air Force Research Laboratory
Correspondent: Click to Email
Compliant substrate technology offers the promise of allowing epitaxial growth of lattice mismatched semiconductors suitable for use in heterogeneous integration. An essential step in realizing a compliant technology is the adequate bonding of the compliant layer to a suitable handle wafer. This work will describe a new wafer bonding facility that allows for precise control of the bonding parameters such as temperature, pressure, atmosphere, and bond processing conditions. The equipment is built around a vacuum furnace fitted with a controllable piston to apply pressure to the bonding wafers. Bonding can be carried out in vacuum or in a variety of inert or reducing atmospheres. The bond furnace is enclosed in a dry box to reduce particle contamination and to reduce atmospheric interactions with bonding surfaces. The equipment is fully computerized to allow for complex bond processing steps. This equipment has been utilized to investigate the effects of various surface chemical treatments of GaAs wafers prior to the bonding process. The technique of arsenic capping of MBE grown buffer layers has been utilized to bond wafers at temperatures as low as 250 °C. Bonding did not occur at 200 °C in agreement with line of sight RGA data that was used to determine the temperatures at which the arsenic was desorbed from the interfaces of the bonding wafers. The conditions used for bonding will be described and characterizations of the interface quality using transmission infrared microscopy and acoustic wave microscopy will be given. Except for occasional particles in the bond interfaces it is possible with this approach to obtain consistently bonded wafers. Comparisons with other surface treatments such as use of epitaxial ready wafers and wafers prepared using conventional etching techniques known to have approximately 2.5nm of oxide present will also be given.