ION-IMPLANTATION PROCESS FOR FORMING IC WAFER WITH BURIED-ZENER DIODE AND IC STRUCTURE MADE WITH SUCH PROCESS

摘要

A new process making it possible to produce stable buried Zener diodes in large-sized wafers where slow ramping of diffusion temperatures is required to avoid crystal damage and other adverse effects. The process includes an initial deep ion implantation of p type dopant (boron). A second ion implantation of n type dopant (arsenic) is made over the p type implantation. Both implantations are driven in to the required degree. An additional p type dopant diffusion is made coincident with the base formation by ion implantation to establish connection to the original deep p-doped region, and an additional n type dopant diffusion is made coincident with the emitter formation to establish connection with the n type dopant implantation.