GALLIUM-ARSENIDE PROBES FOR SCANNING NEAR-FIELD PROBE MICROSCOPY

Gallium arsenide is introduced as a material for the fabrication of no vel probes for scanning probe microscopy (SPM). Compared to convention al probe materials (silicon, silicon nitride), III/V semiconductors su ch as gallium arsenide offer exceptional material properties: a direct band gap appropriate for the fabrication of optical sensors, high ele ctron mobility necessary for high-frequency devices, and high electric al resistance exploited to reduce electrical losses in microwave guide applications. We report on novel developments in the field of gallium arsenide cantilevers with integrated tips for SPM applications. As a result of an intensive study of the gallium arsenide etching behavior we are able to adapt the tip shape to the requirements in SPM, for exa mple, high aspect ratio, minimized radius of curvature, and low surfac e roughness. These cantilevers represent the basic sensor design for b oth, passive as well as active scanning near-field probes. As a first approach, for an active SPM probe a Schottky diode integrated in the t ip apex was produced. First results an the thermal and optical charact erization of Schottky diode probes are presented. High-frequency measu rements of a coplanar microwave guide made of semi-insulating GaAs in comparison to silicon were carried out. Additionally, concepts for a l ight-emitting diode and a laser diode integrated in a tip a challenge for future concepts in SNOM - are discussed.