第9章电子信息类专业英语[李白萍].ppt

Unit Nine Microelectronics;Passage A Introduction to Microelectronics 　　The exploring of space and the development of earth satellites has increased the importance of reducing the size and weight of electronic circuits. Also, even though electricity flows quite rapidly in computers the time delay of the signal in the interconnections between electronic components is an important consideration. If the interconnections are reduced in size, a computer can perform operations at a faster speed. 　　Microelectronics involves the miniaturization of regular electronic circuits. A complete electronic circuit, an operational amplifier for example, which contains large numbers of individual interconnected components, such as diodes resistors, transistors, etc. may be formed on a very small single substrate. The complete miniaturized circuit is then called an integrated circuit.;　　Integrated circuits are small, light, rugged, and reliable. They require less power and lower voltages than equivalent macroscopic circuits; consequently they operate at lower temperatures, and individual components may be close together without exceeding the operating temperature limit. Relatively little stray capacitance and short time delays are produced because of the short interconnections between the individual components in IC. Maintenance is simplified because if a component of the IC fails the complete IC is usually replaced. Mass production techniques of plane technology have reduced the cost of many IC so that they are almost as inexpensive as a single transistor. Eventually most conventional circuits will be replaced by IC.;　　There are two types of basic integrated circuit: monolithic integrated circuit and the thin or thick film. Monolithic IC are constructed in a single substrate of single crystal semiconductor, usually silicon. Thin or thick films IC are formed on the surface of an insulating material such as glass or a ceramic. Hybrid IC contains more than a single substrate, the term h