Ni Schottky barrier on heavily doped phosphorous implanted 4H-SiC

TL;DR

This paper investigates the electrical behavior and current transport mechanisms of Ni Schottky barriers on heavily doped 4H-SiC, revealing thermionic-field emission dominance in forward bias and complex mechanisms in reverse bias.

Contribution

It provides new insights into the current transport mechanisms in Ni/4H-SiC Schottky diodes, especially under different bias conditions and high doping levels.

Findings

Thermionic-field emission dominates forward current transport.

Reverse bias leakage current increases with temperature due to implantation damage.

Field emission becomes significant at higher reverse biases.

Abstract

The electrical behavior of Ni Schottky barrier formed onto heavily doped (ND>1019 cm-3) n-type phosphorous implanted silicon carbide (4H-SiC) was investigated, with a focus on the current transport mechanisms in both forward and reverse bias. The forward current-voltage characterization of Schottky diodes showed that the predominant current transport is a thermionic-field emission mechanism. On the other hand, the reverse bias characteristics could not be described by a unique mechanism. In fact, under moderate reverse bias, implantation-induced damage is responsible for the temperature increase of the leakage current, while a pure field emission mechanism is approached with bias increasing. The potential application of metal/4H-SiC contacts on heavily doped layers in real devices are discussed.