Thin layer high-voltage junction FET (resurf JFET)

The application of Resurf layers [1] especially in relation to high-voltage silicon JFETs is described. Because the breakdown voltage in Resurf devices is in principle determined by the high-ohmic substrate, the possibility is opened to make high-voltage JFETs in very thin, relative highly doped top layers. By making use of a profiled instead of a constant impurity doping concentration in these layers, the drain saturation current can be enlarged considerably while the same channel thickness is maintained.