SEMICONDUCTOR FUNDAMENTALS

SEMICONDUCTOR FUNDAMENTALS

OBJECTIVES Identify three semiconductor devices.   Identify three semiconductor devices. Describe some of the uses of semiconductor devices in electronic equipment. List at least five advantages semiconductor devices have over other components having similar capabilities.

ENABLING OBJECTIVES Identify the two most commonly used semiconductor materials and identify their majority and minority current carriers.   Describe the crystal lattice structure of semiconductors. Describe the electrical characteristics of semiconductors. Describe the difference between intrinsic and doped semiconductors.

ENABLING OBJECTIVES 8. Define the term “hole” as applied to semiconductors.   Recognize the difference between majority carriers and minority carriers in a doped semiconductor. Explain the terms trivalent and pentavalent and explain why they are used.

SILICON AND GERMANIUM ATOMS Silicon and germanium are the most common semiconductor materials with silicon being much more widely-used.

LATTICE STRUCTURE INTRINSIC (PURE) SEMICONDUCTOR Intrinsic, or pure semiconductors have four valence electrons and exist in a lattice structure. Intrinsic semiconductors are poor conductors.

N-TYPE DOPING Pentavalent materials add an additional (donor) electron to the structure. An impurity that increases the number of free electrons creates an N-type semiconductor. Arsenic and phosphorus are examples of pentavalent N-type doping materials.

N-TYPE SEMICONDUCTOR Electrons are majority carriers in N-type material.

P-TYPE DOPING Trivalent materials lack the fourth electron and thus create a hole in the structure. An impurity that reduces the number of free electrons, causing more holes, creates a P-type semiconductor. Gallium and boron are examples of trivalent P-type doping materials.

P-TYPE SEMICONDUCTOR Holes are majority carriers in P-type material.

DOPED SEMICONDUCTORS Doped silicon or germanium remain electrically neutral.

PN JUNCTION CHARACTERISTICS

BARRIER VOLTAGE

FORWARD / REVERSE BIAS Forward Bias Reverse Bias

ENABLING OBJECTIVES Identify three semiconductor devices.   Identify three semiconductor devices. Describe some of the uses of semiconductor devices in electronic equipment. List at least five advantages semiconductor devices have over other components having similar capabilities.

ENABLING OBJECTIVES Identify the two most commonly used semiconductor materials and identify their majority and minority current carriers.   Describe the crystal lattice structure of semiconductors. Describe the electrical characteristics of semiconductors. Describe the difference between intrinsic and doped semiconductors.

ENABLING OBJECTIVES 8. Define the term “hole” as applied to semiconductors.   Recognize the difference between majority carriers and minority carriers in a doped semiconductor. Explain the terms trivalent and pentavalent and explain why they are used.