| 摘要 |
<p>The junction field effect transistors (JFETs) of this invention have improved breakdown voltage capability, reduced on-resistance and improved overdrive capability. The on-resistance of JFET (2000) is decreased by ion-implanting an insulating layer (2006A, 2006B, 2006C, 2016D) covering a layer (2002) that contains source (2005) and gate (2003, 2004) regions of the unipolar transistor. To improve the overdrive capability of a JFET (2000) a region of conductivity (2015) opposite to the conductivity of gate region (2003) is formed in the gate region of the transistor. The second junction in gate region (2003) of this invention prevents the gate-to-source junction from becoming forward biaised until higher gate voltages are applied and thereby provides increased overdrive capability. A new method is used to form a guard ring (2050, 2051) surrounding the active area of a JFET (2000). JFET (2000) formed using this method has a guard ring (2050, 2051) of a second conductivity type extending a first distance D1 into a layer (2002) having a first conductivity type and a gate region of the second conductivity type extending a second distance D2 into layer (2002).</p> |
