What Is a Power MOSFET?

A power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is a field-effect transistor with a MOS structure. The structure of power MOSFETs is classified into horizontal type and vertical type, and the main products of our power MOSFETs are vertical type. Vertical type is classified into planar type and trench type.
The following figure shows an example of a section view of a planar power MOSFET (N-channel). This section describes a planar power MOSFET (N-channel) as an example. In vertical power MOSFETs in which the current flows in the vertical direction, the on-resistance per chip area is reduced because of miniaturization.

Features of Power MOSFETs

The features of power MOSFETs when compared with bipolar transistors and IGBTs are shown below.

Item	Power MOSFET	Bipolar Transistor	IGBT
Structure (arrows indicate the direction of the drain current / collector current)	N-channel	NPN
Circuit Diagram
Control Systems	Voltage control	Current control	Voltage control
Driving Power	Small	Large	Small
Switching Speed	Fast	Slow	Medium
Breakdown Voltage	About 30 V to 800 V	About 50 V to 800 V	About 400 V to 1200 V
Increasing the Current	Easy (about 1 A to 100 A)	Difficult (about 2 A to 25 A)	Easy (about 15 A to 40 A)
Applications	Low Stepping Motor Low-voltage/high-voltage brushless DC motor Switching power suply	Audio Low-voltage/high-voltage brushless DC motor Solenoid	High-voltage brushless DC motor Inverter