AVS 50th International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP13
Structure-optimized CoSi@sub 2@-buried-metal-layer Substrates for IRRAS Fabricated by Wafer-bonding

Tuesday, November 4, 2003, 5:30 pm, Room Hall A-C

Session: Poster Session
Presenter: S. Yamamura, The Graduate University for Advanced Studies, Japan
Authors: S. Yamamura, The Graduate University for Advanced Studies, Japan
S. Yamauchi, DENSO Research Laboratories, Japan
S. Watanabe, Fujitsu Laboratories Ltd., Japan
T. Urisu, Institute for Molecular Science, Japan
Correspondent: Click to Email
The conventional IRRAS (infrared reflection absorption spectroscopy) is applicable only for the metal substrates. So, the IRRAS using buried metal layer (BML) substrates has been developed to apply this technique to the semiconductor surfaces. To obtain high sensitivity in BML-IRRAS, it is essentially important to control the top Si layer thickness less than 200 nm. In this work, we have successfully fabricated a BML substrate with 200 nm thick top Si layer by wafer-bonding for the first time using a SOI wafer having controlled thickness (260 nm) of Si layer. Comparing with the ion implantation method, the wafer bonding method has advantages of (1) atomically flat top Si surface, and (2) unnecessariness of epitaxial growth process, which is essentially required in the ion implantation method to remove the ion implantation damage. The fabrication process is as follows; (1) overlapping of a Co (~ 200 nm thickness) deposited Si wafer on the SOI wafer with face to face, (2) annealing at 800°C for 30 min under N@sub 2@ atmosphere, (3) polishing of the back side Si layer of SOI to ~ 100 nm, followed by complete removal by 10 % KOH solution etching at 70°C for 3 ~ 4 h, and (4) the residual top SiO@sub 2@ layer was removed by etching using 2.5 % HF solution, and the Si(100)/CoSi@sub 2@/base Si(100) BML substrate was obtained. The preliminary formation of thin (100 nm) SiO@sub 2@ layer on the SOI surface was effective to reduce the interface roughness between the top Si and the CoSi@sub 2@ layers. The self-assembled alkyl monolayer was deposited on the BML substrate, and its IRRAS was observed in the wide frequency range from stretching to bending regions.