Semiconductor Diodes
Diode- it is the simplest of semiconductor devices but plays a very vital role in electronic systems, having characteristic that closely
match those of a simple switch.
- the characteristics of an ideal diode are those of a switch that can conduct current in only one direction
- the ideal diode, therefore, is a short circuit for the region of conduction
- the ideal diode, therefore, is an open circuit in the region of non conduction
Semiconductor- is a material that has a conductivity level somewhere between the extremes of an insulator and a conductor.
Conductor- is applied to any material that will support a generous flow of charge when a voltage source of limited magnitude is applied
across its terminals.
Insulator- is a material that offers a very low level of conductivity under pressure from an applied voltage source.
Resistivity- is often used when comparing the resistance levels of materials.
Germanium (Ge) and Silicon (Si)- two materials that have received the broadest range of interest in the development of semiconductor
devices.
Doping - the ability to change the characteristics of the material,
- the process of adding impurity to a pure crystal.
crystal - one complete pattern of atoms of both materials
lattice - the periodic arrangement of the atoms
Covalent bonding- A bonding of atoms, strengthened by the sharing of electrons
Intrinsic materials - semiconductors that have been carefully refined to reduce the impurities to a very low level—essentially as pure as
can be made available through modern technology
An increase in temperature of a semiconductor can result in a substantial increase in the number of free electrons in the
material.
Semiconductor materials such as Ge and Si that show a reduction in resistance with increase in temperature are said to have a
negative temperature coefficient.
An increase in temperature therefore results in an increased resistance level and a positive temperature coefficient.
Extrinsic material - semiconductor material that has been subjected to the doping process
n-type and p-type- two extrinsic materials of immeasurable importance to semiconductor device fabrication.
n-type - created by introducing those impurity elements that have five valence electrons (pentavalent), such as antimony, arsenic, and
phosphorus.
in an n-type material the electron is called the majority carrier and the hole the minority carrier
Donor atoms- diffused impurities with five valence electrons.
P-type material- formed by doping a pure germanium or silicon crystal with impurity atoms having three valence electrons, such as
boron, gallium, and indium
in a p-type material the hole is the majority carrier and the electron is the minority carrier
Acceptor atoms - the diffused impurities with three valence electrons
Depletion region - region of uncovered positive and negative ions; due to the depletion of carriers in this region
- region void of free carriers and therefore unable to support conduction through the region.
Reverse saturation current- current that exists under reverse-bias conditions.
Saturation- comes from the fact that it reaches its maximum level quickly and does not change significantly with increase in the reverse-
bias potential,
Diode- it is the simplest of semiconductor devices but plays a very vital role in electronic systems, having characteristic that closely
match those of a simple switch.
- the characteristics of an ideal diode are those of a switch that can conduct current in only one direction
- the ideal diode, therefore, is a short circuit for the region of conduction
- the ideal diode, therefore, is an open circuit in the region of non conduction
Semiconductor- is a material that has a conductivity level somewhere between the extremes of an insulator and a conductor.
Conductor- is applied to any material that will support a generous flow of charge when a voltage source of limited magnitude is applied
across its terminals.
Insulator- is a material that offers a very low level of conductivity under pressure from an applied voltage source.
Resistivity- is often used when comparing the resistance levels of materials.
Germanium (Ge) and Silicon (Si)- two materials that have received the broadest range of interest in the development of semiconductor
devices.
Doping - the ability to change the characteristics of the material,
- the process of adding impurity to a pure crystal.
crystal - one complete pattern of atoms of both materials
lattice - the periodic arrangement of the atoms
Covalent bonding- A bonding of atoms, strengthened by the sharing of electrons
Intrinsic materials - semiconductors that have been carefully refined to reduce the impurities to a very low level—essentially as pure as
can be made available through modern technology
An increase in temperature of a semiconductor can result in a substantial increase in the number of free electrons in the
material.
Semiconductor materials such as Ge and Si that show a reduction in resistance with increase in temperature are said to have a
negative temperature coefficient.
An increase in temperature therefore results in an increased resistance level and a positive temperature coefficient.
Extrinsic material - semiconductor material that has been subjected to the doping process
n-type and p-type- two extrinsic materials of immeasurable importance to semiconductor device fabrication.
n-type - created by introducing those impurity elements that have five valence electrons (pentavalent), such as antimony, arsenic, and
phosphorus.
in an n-type material the electron is called the majority carrier and the hole the minority carrier
Donor atoms- diffused impurities with five valence electrons.
P-type material- formed by doping a pure germanium or silicon crystal with impurity atoms having three valence electrons, such as
boron, gallium, and indium
in a p-type material the hole is the majority carrier and the electron is the minority carrier
Acceptor atoms - the diffused impurities with three valence electrons
Depletion region - region of uncovered positive and negative ions; due to the depletion of carriers in this region
- region void of free carriers and therefore unable to support conduction through the region.
Reverse saturation current- current that exists under reverse-bias conditions.
Saturation- comes from the fact that it reaches its maximum level quickly and does not change significantly with increase in the reverse-
bias potential,
