Improvement of the drain breakdown voltage of GaAs power MESFET's by a simple recess structure

Abstract

Dependence of the drain-to-source breakdown voltage on the drain structure of GaAs power FET's was investigated. It was found that the drain breakdown voltage is improved by a simple recess structure without surface n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> contact layer. This is due to relaxation of the field at the drain region by increase of the thickness of the active epitaxial layer. The GaAs MESFET with this simple recess structure could be operated up to 24 V. There was no explicit difference in the microwave properties of both recess structure devices with and without the n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> contact layer. As a practical device, an output power of more than 3 W with 4-dB gain is obtained at 6.5 GHz from this simple recess and cross-over structure GaAs FET.