Tag: Semiconductor electronics
-
Gunn Diode – Features, Operation & Applications
Features of a Gunn Diode A gunn diode is made up of only N-type semiconductor which is typically sandwiched between two metal conductors. The central section is usually lightly doped N– surrounded by heavily doped N+ layers. The central section is N-gallium arsenide whereas the two outer sections undergo epitaxial growth from GaAs with increased…
-
PIN Diode – Features & Applications
PIN diode is characterized by fast low capacitance switching. A PIN diode is fabricated in a similar fashion to a silicon switching diode with an intrinsic region added between the PN junction layers. This generates a thicker depletion region, the insulating layer at the junction of a reverse biased diode. This results in lower capacitance…
-
Schottky Diode – Features & Applications
Schottky diode is fabricated as a metal-to-N junction rather than a P-N semiconductor junction. Also referred to as hot-carrier diodes, Schottky diodes are characterized by fast switching times (low reverse-recovery time), low forward voltage drop (normally 0.25 to 0.4 volts for a metal-silicon junction), and low junction capacitance. The forward voltage drop (VF), reverse-recovery time…
-
Metal Oxide Semiconductor FET (MOSFET)
The Metal oxide semiconductor FET (MOSFET) also known as the insulated-gate FET (IGFET) is similar to JFET but exhibits even larger resistive input impedance due to the thin layer of silicon dioxide that is used to insulate the gate from the semiconductor channel. This insulating layer forms a capacitive coupling between the gate and the…
-
The Junction Field Effect Transistors (JFET)
The bipolar transistor has several disadvantages: it has low input impedance because of forward biased emitter junction, it has small high-frequency gain, it has considerable noise level and it is non-linear when |VCE| < 2V. Although low input impedance problem may be improved by careful design and use or more than one transistor, even so…
-
Bipolar Junction Transistors (BJT)
By placing two PN junctions together we can create a bipolar junction transistor. In a PNP transistor the majority charger carriers are holes and typically germanium is favored for these devices. In NPN transistors the majority charger carriers are electrons; for this case, silicon is typically used. The thin and lightly doped central region is…
-
Semiconductor Diodes
A diode is a device that allows current to flow only in one direction. It is made from p-type or n-type semiconductors joined together. It has a depletion layer/p-n junction/potential barrier. How the depletion layer is formed The depletion layer is formed when a p-type and n-type are joined. The electrons in the n-type semiconductor…
-
The Basics of Semiconductor Physics as the Foundation of Electronics
Metals have a large number of weakly bound electrons in what is called their conduction band. When an electric field is applied to a metal such as copper, the electrons migrate freely producing a current through the metal. Because of the ease by which large currents can flow in metals, they are called conductors. In…