What is the difference between Signal Level Semiconductor device and Power Semiconductor Device?

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How the Power Semiconductor devices differ from signal level semiconductor devices?

The power semiconductor devices are not same as signal level semiconductor devices. In general, symbol of the power devices and the respective signal level devices are one and same. But their construction (structure) will differ entirely.

• The power devices will handle very high voltages and currents. i.e. their power handling capability is very high. 
• To meet this requirement, most of the power devices have n^- region called drift region. 
• The width of this drift region determines the breakdown voltage of the device. 
• It makes the construction of power devices become complex. 
• This drift region is not available in normal signal level semiconductor devices.

Example:
The signal diode and power diode has the same symbol.


Signal diode is a two terminal, two layer, PN Junction device.


Whereas, Power diode is a two terminal,PN Junction diode which has p⁺, n^-, n⁺ layers.