INCREASING THE CURRENT DRIVING CAPABILITY OF EPITAXIAL SCHOTTKY BARRIER DIODES USING HIGH-ENERGY IMPLANTATION.

Abstract

Schottky barrier diodes are widely used in bipolar memory cells and logic circuits. The thickness of the epitaxial layer on which bipolar integrated circuits are built is inevitably optimized for the design of n-p-n transistors. The authors describe the use of high-energy implantation to increase the current driving capability of a Schottky diode. The high-energy implantation introduces a deep heavily-doped layer which reduces the series resistance of the epitaxial layer. A small reduction in the barrier height would be expected due to a slightly higher Fermi level near the surface caused by the implantation tail. The damage profile due to the implantation locates much farther away from the surface as compared with the shallow implantations used to reduce the barrier height and hence will affect the reverse leakage only when the depletion region touches the damaged region which occurs at large reverse bias close to the breakdown voltage corresponding to the effective epi-layer thickness after implantation.