Conductivity between conductor and insulator material is called Semiconductor . Semiconductor materials are a class of semiconductor properties, can be used to produce semiconductor devices and integrated power Electronic Material, its conductivity 10 (U-3) ~ 10 (U-9) ohms / cm range. The electrical properties of semiconductor material to light, heat, electricity, magnetism and so very sensitive to external factors, in the semiconductor material mixed with a small amount of impurity can control the conductivity of these materials. It is these properties of semiconductor materials used only to produce versatile semiconductor devices. Semiconductor materials are the basis for the semiconductor industry, the development of semiconductor technology have a great impact. Semiconductor materials by chemical composition and internal structure, can be divided into the following categories. 1. Elemental semiconductors are germanium, silicon, selenium, boron, tellurium, antimony and other. 50′s, germanium in the semiconductor dominant, but the temperature of germanium semiconductor devices and anti-radiation properties are poor, to the late 60s were gradually replaced by silicon. Semiconductor devices made with silicon, high temperature and good resistance to radiation, particularly suitable for production of high-power devices. Thus, silicon has become the most widely used conductor material by a current IC Most of silicon material. 2. Compound semiconductors from the two or more compounds of elements made of semiconductor materials. Its many types, it is important there is gallium arsenide, restrain, imprison antimonide, silicon carbide, silicon and so on CdS and GaAs. Which is the manufacture of microwave GaAs devices and integrated circuits of the important material. SiC because of its strong anti-radiation, high temperature and chemical stability, in the field of space technology has been widely used. 3. Amorphous semiconductor materials for the semiconductor crystal glass is a non-amorphous semiconductor materials, divided into oxide glass and two non-oxide glass. Such material has good Switch And memory characteristics and strong resistance to radiation, mainly used to produce threshold Switch Memory switch and solid display devices. 4. Organic conductor materials by organic semiconductor materials are known to have dozens of species, including naphthalene, anthracene, polyacrylonitrile, phthalocyanines, and some aromatic compounds, has not yet been applied.
Characteristics and parameters Conductivity of semiconductor materials very sensitive to certain trace impurities. High purity semiconductor material is called intrinsic semiconductor, the resistivity at room temperature is high, is a poor conductor of electricity. Doped semiconductor materials in high purity suitable impurities, due to the impurity atoms to provide conductive carriers, the resistivity of the material greatly reduced. This often referred to as impurity semiconductor doped semiconductor. Impurities in the semiconductor conduction band electronic conduction through said N-type semiconductors, hole conduction through the valence band is called P-type semiconductor. Between different types of semiconductor contacts (form PN junction), or semiconductor and metal contacts, the electronic (or hole) concentration difference resulting from the proliferation of the barrier formed at the contact, which has a one-way electrical conductivity of such contacts. PN junction using one-way electrical conductivity, can be made into semiconductor devices with different functions, such as diodes, Transistor And thyristor. In addition, semiconductor materials, electrical conductivity of the external conditions (such as heat, light, electricity, magnetism and so on) were very sensitive, thus able to create a variety of Sensor For information conversion.
Parameters of semiconductor materials with band gap, resistivity, carrier mobility, non-equilibrium carrier lifetime and dislocation density. Band gap semiconductor electronic states by the atomic configuration which reflects the composition of the material atom bound state of valence electron excitation from the energy required to free state. Resistivity, carrier mobility reflects the conductivity of the material. Non-equilibrium carrier lifetime in the outside world to reflect the role of semiconductor materials (such as light or electric field) within the carrier under the equilibrium state by the non-equilibrium transition to the relaxation characteristics. Crystal dislocation is most common type of defect. The dislocation density single crystal semiconductor material used to measure the degree of lattice integrity, for the amorphous semiconductor materials, are not the parameters. Parameters of semiconductor materials can not only reflect the semiconductor material and other non-semiconductor material difference between, more importantly, to reflect a variety of semiconductor materials and even between the same material in different situations, different value of its properties.
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