High power rectifier

Abstract

A high power rectifier device has an − drift layer on an N+ layer. A number of trench structures are recessed into the drift layer opposite the N+ layer; respective mesa regions separate each pair of trenches. Each trench structure includes oxide side-walls and an oxide bottom, and is filled with a conductive material. A metal layer contacts the trench structures and mesa regions, forming Schottky contacts at the metal-mesa interface. Shallow P regions extend from the bottom of each trench into the drift layer. Forward conduction occurs when the Schottky contact's barrier height is overcome. When reversed-biased, depletion regions form around the shallow P regions and the oxide side-walls which provide potential barriers across the mesa regions that shield the Schottky contacts from high electric fields, providing a high reverse blocking voltage and reducing reverse leakage current. The device's unipolar structure provides low switching losses, enabling high switching speeds while reducing the power that must be dissipated when transitioning from forward conduction to reverse blocking mode.