Electronics: Diodes and Transistors

Diodes

• A type of semiconductor device with two terminals (anode and cathode)
• Allows current to flow in one direction but blocks it in the other
• Types:
  • Rectifier diodes: convert AC to DC
  • Zener diodes: regulate voltage
  • LED (Light Emitting Diode): emits light when current flows
  • Photodiodes: converts light into electrical current

Transistors

• A type of semiconductor device with three terminals (base, collector, and emitter)
• Amplifies or switches electronic signals
• Types:
  • Bipolar Junction Transistors (BJTs): uses both positive and negative charge carriers
  • Field-Effect Transistors (FETs): uses voltage to control current flow
  • Unipolar Junction Transistors (UJTs): similar to BJTs but with a single type of charge carrier

Integrated Circuits (ICs)

• A set of electronic components (e.g. transistors, diodes, resistors) on a single piece of semiconductor material
• Designed to perform a specific electronic function
• Types:
  • Analog ICs: process continuous signals
  • Digital ICs: process discrete signals
  • Mixed-Signal ICs: process both analog and digital signals

Fabrication Process

• A series of steps to create semiconductor devices:
  1. Wafer preparation: produce a silicon wafer
  2. Layer formation: deposit and pattern layers of material (e.g. insulators, conductors, semiconductors)
  3. Doping: introduce impurities to alter the semiconductor's electrical properties
  4. Etching: remove material to create patterns
  5. Metallization: add metal interconnects
  6. Packaging: assemble and protect the device

Device Physics

• P-N Junction: a region where p-type (positive) and n-type (negative) semiconductor materials meet
• Depletion region: a region near the p-n junction where charge carriers are depleted
• Bandgap energy: the energy difference between the valence and conduction bands of a semiconductor material
• Carrier mobility: the ease with which charge carriers move through a semiconductor material

Diodes

• A diode has two terminals: an anode and a cathode.
• Diodes allow current to flow in one direction but block it in the other.
• Rectifier diodes convert AC to DC.
• Zener diodes regulate voltage.
• LED (Light Emitting Diode) emits light when current flows.
• Photodiodes convert light into electrical current.

Transistors

• A transistor has three terminals: base, collector, and emitter.
• Transistors amplify or switch electronic signals.
• Bipolar Junction Transistors (BJTs) use both positive and negative charge carriers.
• Field-Effect Transistors (FETs) use voltage to control current flow.
• Unipolar Junction Transistors (UJTs) are similar to BJTs but with a single type of charge carrier.

Integrated Circuits (ICs)

• ICs are a set of electronic components on a single piece of semiconductor material.
• ICs are designed to perform a specific electronic function.
• Analog ICs process continuous signals.
• Digital ICs process discrete signals.
• Mixed-Signal ICs process both analog and digital signals.

Fabrication Process

• Wafer preparation involves producing a silicon wafer.
• Layer formation involves depositing and patterning layers of material (e.g. insulators, conductors, semiconductors).
• Doping introduces impurities to alter the semiconductor's electrical properties.
• Etching removes material to create patterns.
• Metallization adds metal interconnects.
• Packaging involves assembling and protecting the device.

Device Physics

• A P-N Junction is a region where p-type (positive) and n-type (negative) semiconductor materials meet.
• The depletion region is a region near the p-n junction where charge carriers are depleted.
• Bandgap energy is the energy difference between the valence and conduction bands of a semiconductor material.
• Carrier mobility is the ease with which charge carriers move through a semiconductor material.