LOW CAPACITANCE AND HIGH-HOLDING-VOLTAGE TRANSIENT-VOLTAGE-SUPPRESSOR (TVS) DEVICE FOR ELECTRO-STATIC-DISCHARGE (ESD) PROTECTION

摘要

A well-less Transient Voltage Suppressor (TVS) Silicon-Controlled Rectifier (SCR) has a P+ anode region (20) that is not in an N-well (62). The P+ anode region (20) is surrounded by N+ isolation regions (22, 24) near the surface, and a deep N+ region (30) underneath that is formed in a p-substrate (64). An N+ cathode region (40) is formed in the p-substrate (64). The deep N+ region (30) has a doping of 5 x 10 ¹⁸ to 5 x 10 ¹⁹/cm ³, compared to a doping of 1 x 10 ¹⁶/cm ³ for a typical N-well (62), or a doping of 1 x 10 ¹³ to 1 x 10 ¹⁵/cm ³ for the p-substrate (64). The high doping in the deep N+ region (30) causes a recombination current that can shunt half of the anode current (IA). Since the deep N+ region (30) is much shallower than an N-well (62), the sidewall capacitance is greatly reduced, allowing for higher speed applications.