New Zener Diode Structure Between Base and the Collector Using Retrograded Profile

A new Zener diode structure for bipolar transistor is proposed and analyzed. By placing the Zener diode at junction termination, we could obtain stable clamped breakdown voltage without deterioration of device performance. P+ layer of the Zener diode is embedded with base of transistor simultaneously so that whole functional behaviors of the composite transistor could be realized with relatively simple process. The breakdown voltage of the Zener diode is controlled only by adjusting of the phosphorus implantation dose. The breakdown voltage distribution of the fabricated Zener diode is less than ±4%. The BV_CBO and BV_CEO of bipolar transistors are about 50 V, same as the breakdown voltage of Zener diodes. And the DC current gain is 300 at V_CE=2 V and I_C=0.5 A