POWER SEMICONDUCTOR DEVICES

POWER SEMICONDUCTOR :

A "semiconductor" is a substance that, as its name suggests, is characterized for "conducting" electricity easily, while at the same time, working as an "insulator" to prevent the flow of electricity. By using semiconductors, it becomes possible to perform "rectification" for the one-directional flow of electricity, "amplification" for increasing electrical signals, and "switching" to open and close the flow of electricity.

Power semiconductors can handle high voltages and large currents. They possess a structure that is different from regular semiconductors, enabling them to handle high voltages and large currents without damage. Failures may occur due to a rise in temperatures resulting from heat generated from handling large power. Therefore, we have worked to develop ways to reduce the amount of power semiconductor loss, which is the cause of the heat generation, while also effectively releasing the generated heat to the outside.

Power semiconductor devices are semiconductor devices used as switches or rectifiers in power electronic circuits (switch mode power supplies for example). They are also called power devices or when used in integrated circuits, called power ICs.
Some common power devices are the power diode, thyristor, power MOSFET and IGBT (insulated gate bipolar transistor). A power diode or MOSFET, for example, operates on similar principles as its low-power counterpart, but is able to carry a larger amount of current and typically is able to support a larger reverse-bias voltage in the off-state.

Research needs in this area include on one hand to increase the maximum power handling capability of the power devices, on the other hand include the need to increase the speed they can switch. Power semiconductor is also the key in determining the power conversion efficiency. NCSU's research concentration is on power devices that use wide bandgap semiconductor materials (e.g. SiC and GaN).

Research projects are focused on the analysis of power device structures using numerical simulations and the development of analytical models based on semiconductor transport physics. Students are encouraged to validate the theoretical analysis using electrical characterization of commercially available devices and by the fabrication of novel device structures. The impact of improvements in power device characteristics on specific applications allows an understanding of trade-offs between on-state characteristics, reverse blocking capability, and switching performance.This technical  is dedicated to the review of the following power electronics devices which act as solid-state switches in the circuits. They act as a switch without any mechanical movement. Power devices is divided into terms of their number of terminals: – The two-terminal devices (diodes) whose state is completely dependent on the external power circuit they are connected to. – The three-terminal devices, whose state is not only dependent on their external power circuit, but also on the signal on their driving terminal (gate or base).

1.  Power Diodes
2.  Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET)
3. Bipolar -Junction Transistor (BJT)
4. Insulated-Gate Bipolar Transistor (IGBT)
5. Thyristors (SCR, GTO, MCT)