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

Invited Paper SC2+EL+SS-MoM1
Integration of Epitaxial Oxide and Nitride Heterostructures with Dissimilar Substrates by Pd-In Wafer Bonding and Laser Lift-off

Monday, October 2, 2000, 8:20 am, Room 312

Session: Dissimilar Materials
Presenter: T. Sands, University of California, Berkeley
Authors: T. Sands, University of California, Berkeley
W.S. Wong, University of California, Berkeley
L Tsakalakos, University of California, Berkeley
N.W. Cheung, University of California, Berkeley
Correspondent: Click to Email
The functionality of integrated microsystems can be enhanced through intimate integration of disparate classes of materials. Combining the best materials for their respective functions (e.g., information processing, light emission/detection, and piezoelectric actuation) without sacrificing materials properties is often only possible if the materials are synthesized and processed separately, and subsequently combined. In this talk, a fast, simple and robust "paste-and-cut" method for accomplishing this integration step is described. The process combines low-temperature transient-liquid-phase (TLP) metal bonding with excimer laser lift-off (LLO) to integrate epitaxial group-III nitride (e.g., AlN and InGaN) and perovskite oxide (e.g., PZT and PMN-PT) heterostructures with virtually any substrate, including polymers, stainless steel, and CMOS silicon. Both the TLP and LLO steps are characterized by minimal heating of the receptor substrate, thus maximizing the range of materials classes that may be intimately combined. In our TLP metal bonding process, donor and receptor substrates are coated with Pd/In bilayers and pressure-bonded at 200°C to achieve a high-contact-area PdIn@sub 3@ intermetallic bond with a melting point above 600°C. The L LO process uses a single pulse from a uv laser (e.g., KrF excimer at 248 nm with a pulse length of 38 nsec), irradiating the film/substrate interface through the transparent substrate (sapphire or MgO), to decompose the film at the interface with the substrate. The short pulse duration enables thermal decomposition of the film interface without significant heating of the receptor substrate. Examples of TLP/LLO paste-and-cut integration, including vertical (In,Ga)N light-emitting diodes on Si, and epitaxial ferroelectric (PZT) films on stainless steel, will illustrate the potential of this integration method for the functional enhancement of microsystems. @FootnoteText@ W.S. Wong is now at Xerox PARC, Palo Alto, CA.