Improvement of bonding strength between Au Ti and SiO2 films by Si layer insertion

In the fabrication of broad band optical waveguide modulators, a certain te chnology must be used to prepare 15-20-mu m-thick Au electrodes on the SiO2 surface covering the waveguides. A thin transition metal film is commonly inserted between the Bu and SiO2 to improve adhesive strength. The transiti on metal film used in this stud!: is Ti. Hen, the Si02 surface is precoated with Si prior to the Ti film formation, demonstrating a significant improv ement in adhesive strength. The Si layer works as a barrier against oxidati on of the Ti film due to the SiO2, leading to a homogenous film growth of m etallic Ti. (C) 1999 American Vacuum Society. [S0734-2101(99)02503-8].