Application of vacuum technology in information film processing

- Sep 27, 2019-

Application of vacuum technology in information film processing


The history of nearly half a century shows that the development of electronic devices has greatly promoted human society, and each new electronic device has played a positive role in promoting the development of science and technology and production. The birth of vacuum tube is the result of the full development of vacuum science and technology. The development of microelectronic devices is based on the improvement of ultrapure and high precision processing technology of materials, many of which are related to vacuum technology. Microelectronic devices are the basis of modern high-speed computers and personal computers. In some developed countries, microelectronic and computer industries have surpassed energy, materials, transportation and iron and steel industries and accounted for the first national economic output value. In the development of electronic industry and computer industry, vacuum science and technology have made important contributions.


Home appliances in the future will mainly be four major new pieces: a multi-media color TV, computer and audio combination of multi-functional information system; A refrigerator with the functions of vacuum freezing and vacuum preservation; Washing machine with vacuum dewatering function and air conditioner with monitoring indoor air freshness. Some of these household appliances directly apply vacuum technology, while some indirectly use the processing results obtained by vacuum technology. Because whether it is the computer, or all kinds of automatic electrical appliances, their foundation is microelectronic devices. One of the most important is in scale integrated circuits. Nowadays, the mention of microelectronic devices is almost known to everyone, young and old, because its role in the production and life of human society is no other industrial products can be compared with it. The development of microelectronic devices will promote the faster progress of human society. The development trend of microelectronic devices is large scale integrated circuit, which is more and more integrated, that is, the functional components on the chip are smaller and smaller. The pattern, described by Moore's law, is that every 18 months the number of pieces on a chip of the same size doubles. This has been true for the last 20 years, and it will be true for the next 15, according to the cytologists.



Moore's law talks about the density of components on a silicon wafer, a parameter that describes how much information a large scale integrated circuit can process, according to a special report IBM published in 1994 about fancy chips: the smaller the component, the more powerful the chip. The information storage density is 106bit/cm2, which can store a 30-page paper; 108bit/cm2, able to store 10 books of 300 pages; 1010bit/cm2, 1000 books; 1012bit/cm2, with 100,000 books, it is possible to store 5 million books on a 3.5 "disk. This is almost the entire collection of provincial libraries in China. With this increase in the storage density, the function of the chip is amazing. This is only the calculation of quantitative change, which should take into account the functional leap from quantitative change to qualitative change.



1012bit/cm2 is called ultra-high density information storage, which is mainly used for digital 0 and 1 storage. Ampere is the foundation of nano-electronics. Each information storage point is less than 10nm in size and contains a limited number of atoms. As a function point, it is characterized by smaller volume (<109 atoms), purer materials (impurity defects <10-8), lower signal power (<10-12 joules), and faster response time (< nanoseconds) to the signal's write and read than conventional components. Therefore, the research of ultra-high density information storage requires the development of new theories, new materials and new assembly processing technologies.


First used in broadcasting, communications, and radar electronic devices is the vacuum tube, is mainly controlled by the cathode emission to the free electrons in a vacuum, used in signal, detection, amplification, oscillation, modulation, launch storage and processing. Valve device manufacturing, require vacuum clean, health and the generation of microelectronic device is built on the basis of high purity germanium and silicon, in the process of material and devices processing, who asked not to be better than high purity semiconductor pure and highly ordered crystal structure. As for the next generation of nano-electronic devices of microelectronic devices, it is required that the materials used and the assembly process should be better than the semiconductor purity, fewer impurities and defects, and more perfect crystal structure. Therefore, when studying nano-electronic devices, high vacuum or even ultra-high vacuum will be used more for material preparation and device assembly.


In recent years, Peking University and Beijing vacuum physics laboratory of Chinese Academy of Sciences focus on the research of ultra-high density information storage devices for organic composite films. Today's film formation process can maintain a vacuum pure environment, so can get high quality film. Physical vapor deposition (PVD) technology mainly includes evaporation, sputtering, ion plating, molecular beam epitaxy and ion cluster beam plating. After analyzing several techniques of preparing organic functional films by vacuum method, it is concluded that ion group beam (ICB) deposition technique is the most suitable one for preparing organic functional films. It is the material evaporation through adiabatic expansion process, ionization process to form a charged atomic group, after accelerated deposition to the substrate. Atoms have a high mobility on the surface of the substrate, which is conducive to the nucleation and grain growth of the film, forming high-quality film. By controlling the adiabatic process, ionization voltage, acceleration voltage and substrate temperature, the film can be made into crystal, polycrystalline or amorphous film


With ion mass of beam and high vacuum deposition technology was developed for super high density information storage of organic and metal nanofilms, mainly has two kinds: one kind is silver/organic (such as Ag - CPU) composite membrane, using scanning tunneling microscope (STM) voltage pulse write signal spot diameter of 10 nm, stable to write and read 1 s and 0 s signal. The optical storage characteristics of ag-cpu thin films were studied with a semiconductor laser thin film read-write device (wavelength: 780nm). 7.0mw, 1ms wide optical pulse can erase the signal; 1.1mW can read the signal stably.


Another type is organic donor/organic receptor (such as m-nbmn /DAB) nanofilm, whose electrical pulse signal is written at a diameter of 1.3nm, and the corresponding data recording density is 1013bit/cm2. The recorded signal is stable. The scanning tunnel spectrum (STS) analysis of the written signal points shows that the film is an insulator before the signal is written, and a conductor after the signal is written. Such films can also be used for stable writing and reading of optical signals. The result is highly appraized by foreign experts who think it is close to the limit of nano functional components.


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The research results of organic composite information storage film indicate that vacuum technology still plays an important role in the future research of nano-electronic devices. At present, the acquisition and measurement technology of ultra-high vacuum has been mature, but the application of vacuum technology is still a very attractive topic, and a lot of work needs to be developed, especially for the development of the key technology of the future information society -- nano-electronic devices. In the coming 21st century, vacuum technology will play a more and more important role in the information society with the introduction of nano-electronics into various fields.