Power Diode Structure

• It has heavily doped n⁺ region, lightly doped n^- region and heavily doped p⁺ region.
• The n^- layer is known as drift region. This layer is not available in low power diodes.
• The drift region  determines the reverse breakdown voltage of the diode. Its function is to absorb the depletion layer of the reverse biased p⁺n^- junction.
• As it is lightly doped, it will add significant ohmic resistance to the diode when it is forward biased. Thus increase in power dissipation of the device.