Improved SiC Schottky Barrier Diodes Using Refractory Metal Borides

Abstract

This research demonstrates how the deposition temperature of Schottky contacts on 4H-SiC affects the electrical and thermal properties of a Schottky diode. Several refractory metal borides are investigated for the contacts which are deposited at room temperature (20 ⁰C) and high temperature (600 ⁰C). The electrical properties of the diodes are characterized by using current-voltage (I-V) and capacitance-voltage (C-V) measurements. Thermal properties are investigated by using rapid thermal processor (RTP). Schottky contacts which are deposited at 600 ⁰C produced better Schottky diodes with smaller ideality factors from 1.05 to 1.10), barrier heights from 0.94 to 1.15 eV, smaller resistances, and smaller current density in reverse bias conditions when compared to the contacts deposited at room temperature. These values remained stable after annealing in RTP at 600 ⁰C for 20 minutes. The improved electrical properties and thermal stability of the diodes with contacts deposited at 600 ⁰C are related to the removal of O2 from the boride/SiC interface, as revealed by the Rutherford backscattering spectroscopy (RBS) analysis. These results indicate improved electrical and thermal properties of boride/SiC Schottky contacts, making them attractive for high temperature applications.