Integrated Zener diode for gate protection and voltage sourcing in integrated power management platforms

We describe a Zener diode integrated in a 0.18 micron based 60V Power Management Process platform. By adding one ion implant layer, a buried diode with a sharp reverse breakdown current slope is implemented. A steep rise in reverse current, from 10⁻⁸ A to 10⁻³ A is obtained at the breakdown region, over less then 100mV voltage variation. The buried interface has shown no breakdown voltage shifts under prolonged stress measurements at current densities exceeding 2mA/um⁁2, shifts which were clearly observed in surface diodes. By varying the implant dose the reverse breakdown voltage — Vz, can be tuned from 4.5V to 7.5V. Consequently the diode is adequate for voltage sourcing applications and gate protection of the 5V gates utilized by the LDMOS devices in the Power Management Process.