A SCANNING TUNNELING MICROSCOPY SPECTROSCOPY SYSTEM FOR CROSS-SECTIONAL OBSERVATIONS OF EPITAXIAL LAYERS OF SEMICONDUCTORS

We have constructed a new scanning tunneling microscope (STM) using two mechanical stages. One (z stage) is for approaching the tip to the sample surface and the other (x stage) is for one-dimensional movement of the sample to observe a specific area of the sample surface. The stages move so precisely that the distance between the tip and the sample is constant during the sample movement. It enables us to find the specific area quickly. Another feature of the STM is a novel data accessing method which realizes high-speed scanning tunneling spectroscopy (STS) measurement. A great deal of data are accessed at high speed by a personal computer equipped with 32-megabyte random access memory (RAM). Using this system, STM and STS measurements of cleaved (110) surfaces of Ga0.47In0.53 As/InP multiquantum wells were performed in air.