In recent years, the information society has been growing at a remarkable pace, requiring the development of technologies that allow more information to be stored at a high density. At the present time, in the research and development field of semiconductor devices and file memories, transition to nanometer-scale and high-density products is taking place. In the future, technologies that make micro-fabrication and micro-recording at an atomic scale possible will be in even greater demand.
A variety of technologies that make micro-fabrication and microrecording at an atomic scale possible have been proposed. Technologies that are regarded as having a bright prospect in the future include a technology utilizing an STM (Scanning Tunnelling Microscope) technique. It should be noted that the STM technology itself is disclosed in detail in the specification of U.S. Pat. No. 4,343,993.
An example of a fabrication/recording technique at an atomic scale that utilizes the STM technology is described on pages 524 to 526 of "NATURE" Vol. 344 (1990). In this technique, xenon atoms are dispersed and absorbed by a nickel surface held at an ultra-low temperature of 4.degree. K. in an ultra-high vacuum environment. The dispersed and absorbed xenon atoms are then attracted one after another to the tip of an STM probe using the Van der Waal's force working between the STM probe and the xenon atoms, which migrate to a predetermined location on the nickel surface. By repeating this operation again and again, the xenon atoms are arranged along a predetermined character pattern, and the character pattern is then read by using the STM technique. Another example is described on pages 1312 to 1314 of "Appl. Phys. Lett." Vol. 55, No. 13 (1989). In this example, an STM probe is crashed into a specimen surface, mechanically drilling fine holes in order to implement fabrication and recording. The holes are then observed by using the STM technique.
In the case of the first example, however, in order to have xenon atoms absorbed by the nickel surface, it is necessary to put them in an ultra-high vacuum environment at an ultra-low temperature of 4.degree. K. as cited above. Thus, this technique cannot be put to use in the atmosphere at room temperature. In addition, the technique has practically a large problem in that it takes a very long time to arrange xenon atoms along a predetermined character pattern. As for the second technique, since fabrication and recording are carried out by engraving holes mechanically on a specimen surface, it takes a very long time to perform the fabrication and recording. In addition, this technique also has a problem in that a hole with a dimension of the order of 5 nm which is larger in size than an atom may be engraved inadvertently. Accordingly, this technique is practically difficult to implement.
USPTO Backgrounds
USPTO Backgrounds