Trench schottky rectifiers with non-uniform trench depths

Abstract

A design methodology to optimize the drift region doping properties in trench Schottky rectifiers has been presented. Advanced lithography is being used for trench devices that are designed for smaller die sizes in wireless applications. Such devices feature narrow active trenches to maximize active area utilization in combination with a wide termination trench to support the breakdown voltage. Such different trench aspect ratios create a depth mismatch, if they are formed in a single etch step. It has been shown that designing the drift region while accounting for the trench depth difference is vital to properly optimize the device electrical parameters. A new trench architecture has also been proposed which features alternating deeper active trenches. The new trench architecture is shown to have the best performance trade-off at the cost of one additional mask step.