Low-voltage punch-through transient suppressor employing a dual-base structure

摘要

A punch-through diode transient suppression device has a base region of varying doping concentration to improve leakage and clamping characteristics. The punch-through diode includes a first region comprising an n+ region, a second region comprising a p− region abutting the first region, a third region comprising a p+ region abutting the second region, and a fourth region comprising an n+ region abutting the third region. The peak dopant concentration of the n+ layers should be about 1.5E18 cm^−3, the peak dopant concentration of the p+ layer should be between about 1 to about 5 times the peak concentration of the n+ layer, and the dopant concentration of the p− layer should be between about 0.5E14 cm^−3 and about 1.OE17 cm^−3. The junction depth of the fourth (n+) region should be greater than about 0.3 &mgr;m. The thickness of the third (p+) region should be between about 0.3 &mgr;m and about 2.0 &mgr;m, and the thickness of the second (p−) region should be between about 0.5 &mgr;m and about 5.0 &mgr;m.