Measurements with the World's First Scanning Positron Microscope (SPM) (Messung mit dem weltweit ersten Rasterpositronenmikroskop)

摘要

This dissertation describes the development of the world's first scanning positron microscope (SPM) by physicists at the Military University, Munich. The SPM uses positrons, the antiparticle partners of electrons, to detect minute defects in semiconductors. Since positrons are positively charged, they are attracted to regions of negative charge. The most common form of defect in semiconductors is known as a 'vacancy'. When a positron meets an electron, the two annihilate each other, releasing their energy as gamma-ray photons. The resulting radiation reveals the precise location of a vacancy. The positrons, which come from a radioactive sodium source, are passed through a series of electric fields that homogenize them into short pulses. They are then passed through another series of fields that accelerate the pulse to a specified energy before focusing it into a 2 micron dot on the silicon surface.