Photon scanning tunneling microscope and its application for inspection of Al 2 O 3 waveguide film

Abstract

Photon Scanning Tunneling Microscope (PSTM) is a newly developed technique. As a near-field optical microscope, it has the high resolution breaking through the diffraction limit and the advantage for easy to prepare the samples. PSTM is a useful tool in the inspection for many kinds of material film as the image containing the sample's information of topography and refractive index. We have developed a PSTM with resolution 5 to approximately 10 nm and scanning range 6 X 6 micrometer. By making use of two lasers, the false image caused by inclination of sample surface can be reduced. This PSTM is engaged in the inspection of Al<SUB>2</SUB>O<SUB>3</SUB> optical waveguide film made using ion-beam-enhanced-deposition (IBED) technique at different substrate temperature. The PSTM images of the optical waveguide film are obtained and analyzed. The PSTM images show that as the increasing of the substrate temperature during the deposition, the sample images of refractive index and topography tend to smooth and even, consequently the scattering loss can be decreased. The conclusion is that by properly increasing the temperature of the substrate during the deposition period, the scattering loss can be decreased and the property of Al<SUB>2</SUB>O<SUB>3</SUB> optical waveguide can be improved.