Using thin emitters to control BVce0 effects in punch-through diodes for ESD protection

We present results of a novel punch-through diode structure which uses a thin SiGe emitter to effectively suppress impact-ionization related (BV_ce0) effects that typically start to dominate the electrical characteristics of conventional punch-through devices at voltages above 2.5..3.0 V, resulting in the occurrence of negative resistances (snap-back) and severely limiting the application range.