MICRON-SIZE HALL PROBE FOR PRECISION MAGNETIC-FIELD MAPPING

InSb Hall effect probes have been made with active volumes of about 1 μm3. Successive layers of In and Sb were vacuum evaporated onto microscope cover glasses. The layers were annealed and recrystallized to form low-resistivity InSb. However, before recrystallization, a layer of pure In was evaporated onto the InSb. A hierarchy of photoresist patterns was applied to form the Maltese-cross active area together with long lead stripes. The actual pattern was formed either by sputter etching or by ion milling. The final glass probe was 2 mm wide by 25 mm long with the microscopic active area in the center. In use, the glass strip was placed - with the active area out - on a curved mandril.