What is a semiconductor device?
Semiconductor device is an electronic device whose conductivity is between good conductor and insulator. It uses the special electrical characteristics of semiconductor materials to complete specific functions. It can be used to generate, control, receive, transform, amplify signals and convert energy. The semiconductor materials of semiconductor devices are silicon, germanium or gallium arsenide, which can be used as rectifiers, oscillators, light emitters, amplifiers, light meters and other equipment. In order to distinguish from integrated circuits, it is sometimes called discrete devices. The basic structure of most two terminal devices (i.e. crystal diodes) is a PN junction. Semiconductor devices usually use different semiconductor materials, different processes and geometric structures, and have developed a wide variety of crystal diodes with different functions and uses. The frequency coverage of crystal diodes can range from low frequency, high frequency, microwave, millimeter wave, infrared to light wave. Three terminal devices are generally active devices, typically represented by various transistors (also known as crystal triodes). Transistors can be divided into bipolar transistors and field effect transistors. According to different uses, transistors can be divided into power transistors, microwave transistors and low-noise transistors. In addition to the general transistors used for amplification, oscillation and switching, there are also some transistors for special purposes, such as optical transistors, magnetic sensitive transistors, field effect sensors, etc. These devices can not only convert the information of some environmental factors into electrical signals, but also have the amplification effect of general transistors to obtain larger output signals. In addition, there are some special devices, such as monocrystalline tube can be used to generate sawtooth wave, thyristor can be used in various high current control circuits, charge coupled device can be used as rubber photographing device or information memory device, etc. In military equipment such as communication and radar, weak signals are mainly received by semiconductor receivers with high sensitivity and low noise. With the rapid development of microwave communication technology, microwave semiconductors and low-noise devices are developing rapidly, the working frequency is increasing, and the noise figure is decreasing. Microwave semiconductor devices have been widely used in air defense and missile defense, electronic warfare and other systems because of their excellent performance, small volume, light weight and low power consumption.
What is an integrated circuit?
The crystal diode, triode and resistance capacitor are all made on the same silicon chip, which is called integrated circuit. A silicon chip with less than 100 elements is called a small-scale integrated circuit, from 100 to 1000 elements is called a medium-scale integrated circuit, from 1000 to 100000 elements is called a large-scale integrated circuit, and more than 100000 elements are called a very large-scale integrated circuit. Integrated circuit is the basic electronic device necessary for the development of computer. Many advanced industrial countries attach great importance to the development of integrated circuit industry. The integration of integrated circuits is increasing at the rate of doubling every year. 256 kilobit MOS random access memory integrated on each chip has been successfully developed and is exploring to 1 megabit MOS random access memory.
