Smart-Cut Layer Transfer of Single-Crystal SiC Using Spin-on-Glass

The authors demonstrate “smart-cut”-type layer transfer of single-crystal silicon carbide (SiC) by using spinon-glass (SoG) as an adhesion layer. Using SoG as an adhesion layer is desirable because it can planarize the surface, facilitate an initial low temperature bond, and withstand the thermal stresses at high temperature where layer splitting occurs (800–900 °C). With SoG, the bonding of wafers with a relatively large surface roughness of 7.5–12.5 Å rms can be achieved. This compares favorably to direct (fusion) wafer bonding, which usually requires extremely low roughness (<2 >Å rms), typically achieved using chemical mechanical polishing (CMP) after implantation. The higher roughness tolerance of the SoG layer transfer removes the need for the CMP step, making the process more reliable and affordable for expensive materials like SiC. To demonstrate the reliability of the smart-cut layer transfer using SoG, we successfully fabricated a number of suspended MEMS structures using this technology. Disciplines Mechanical Engineering Comments Lee, J., Bargatin, I., Park, J., Milaninia, K., Theogarajan, L., Sinclair, R., & Howe, R. (2012). Smart-Cut Layer Transfer of Single-Crystal SiC Using Spin-on-Glass. Journal of Vacuum Science & Technology B, 30(4), 042001. doi: 10.1116/1.4734006 Copyright 2012 American Vacuum Society. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Vacuum Society. Author(s) Jae-Hyung Lee, Igor Bargatin, Joonsuk Park, Kaveh M. Milaninia, Luke S. Theogarajan, Robert Sinclair, and Roger T. Howe This journal article is available at ScholarlyCommons: http://repository.upenn.edu/meam_papers/293 Smart-cut layer transfer of single-crystal SiC using spin-on-glass Jae-Hyung Lee Department of Electrical Engineering, Stanford University, Stanford, California 94305 Igor Bargatin Department of Electrical Engineering, Stanford University, Stanford, California 94305 and Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, Pennsylvania 19104 Joonsuk Park Materials Science and Engineering, Stanford University, Stanford, California 94305 Kaveh M. Milaninia and Luke S. Theogarajan Electrical & Computer Engineering, University of California, Santa Barbara, California 93106 Robert Sinclair Materials Science and Engineering, Stanford University, Stanford, California 94305 Roger T. Howe Electrical Engineering, Stanford University, Stanford, California 94305 (Received 18 May 2012; accepted 21 June 2012; published 3 July 2012) The authors demonstrate “smart-cut”-type layer transfer of single-crystal silicon carbide (SiC) by using spin-on-glass (SoG) as an adhesion layer. Using SoG as an adhesion layer is desirable because it can planarize the surface, facilitate an initial low temperature bond, and withstand the thermal stresses at high temperature where layer splitting occurs (800–900 C). With SoG, the bonding of wafers with a relatively large surface roughness of 7.5–12.5 Å rms can be achieved. This compares favorably to direct (fusion) wafer bonding, which usually requires extremely low roughness (<2 Å rms), typically achieved using chemical mechanical polishing (CMP) after implantation. The higher roughness tolerance of the SoG layer transfer removes the need for the CMP step, making the process more reliable and affordable for expensive materials like SiC. To demonstrate the reliability of the smart-cut layer transfer using SoG, we successfully fabricated a number of suspended MEMS structures using this technology. VC 2012 American Vacuum Society. [http://dx.doi.org/10.1116/1.4734006]