Introduction to semiconductors

• Are materials which have a conductivity between conductors and non conductors or insulators

  semiconductors
• small amounts of impurities are added to pure semiconductors causing large changes in the conductivity of the material

  doping
• What are the parts of the process of semiconductor assembly

  • Wafer
  • lead frame
  • gold wire
  • copper wire
  • tape n reel
• also known as a valve in British English, is an electronic device used in many older model radios, television sets, and amplifier to control electric current flow


  vacuum tubes
• The cathode is heated, as in a light bulb, so it will emit electrons


  thermionic emission
• the part that accepts the emitted electrons

  anode
• hardly larger than individual transistors, can do the work of hundres of even thousands of vacuum tubes.

  Integrated circuits
• Is widely used in diodes, transistors, and integrated circuits. (Si)


  Silicon
• Other substances or impurities, must be added to 


  silicon to give it the desired properties
• A compound that is used as another common semiconductor. (GaAs)


  Gallium Arsenide
• GaAs requires little or high voltage?

  little
• Which charge carriers move faster through the semiconductor material? Gallium Arsenide or Silicon

  Gallium Arsenide
• GaAs devices are relatively immune to the effects of 


  Ionizing radiation
• Exhibits conductivity that varies depending on the intensity of visible light or IR radiation that strikes it

  selenium
• selenium is useful in making 


  Photocells
• A component or circuit that converts ac to pulsating dc

  rectifier
• Pure elemental germanium is a poor electrical conductor


  it becomes a semiconductor when impurities are added
• Germanium has a low voltage drop


  0.3
• Which semiconductor is easily destroyed by heat

  Germanium
• MOS means?


  Metal oxide semiconductor
• CMOS means?


  Complementary metal oxide semiconductor
• Certain metal oxides have properties that make them useful in the manufacture of semiconductor devices
• Also known as an extremely pure semiconductor

  Intrinsic semiconductor
• In an intrinsic semiconductor, the valence band is completely filled and the conduction band is completely empty
• A semiconductor to which an impurity at a controlled rate is added to make it conductive is known as an


  extrinsic semiconductor
• An intrinsic semiconductor is capable to conduct little current even at room temperature, but it is not useful for the preparation of various electronic devices