The aim of this paper is to review almost a decade of direct-bonding activities at Philips Research including the diversity and feasibility of direct bonding. The bondability of a material is determined by its geometrical shape and mechanical, physical, and chemical surface states. Physically direct bonding provides a vacuumtight bond, which is jointless and glueless, and it permits engineering of the interfaces to be bonded. Layers can be buried, and reflective–lossless bonds between optical elements can be created. A variety of materials are investigated: (refractory) metals, a semimetal, boron, diamond, a carbide, fluorides, nitrides, oxides, and a chalcogenide. The applications that we describe relate to interface engineering, waveguiding, and the direct bonding of a fiber plate.
© 1994 Optical Society of America
Original Manuscript: December 4, 1992
Revised Manuscript: June 7, 1993
Published: March 1, 1994
Jan Haisma, Bert A. C. M. Spierings, Udo K. P. Biermann, and Aart A. van Gorkum, "Diversity and feasibility of direct bonding: a survey of a dedicated optical technology," Appl. Opt. 33, 1154-1169 (1994)