Investigation of Barrier Inhomogeneities and Electronic Transport on Al-Foil/<i>p</i>-Type-4H-SiC Schottky Barrier Diodes Using Diffusion Welding

Abstract

The diffusion welding (DW) is a comprehensive mechanism that can be extensively used to develop silicon carbide (SiC) Schottky rectifiers as a cheaper alternative to existing mainstream contact forming technologies. In this work, the Schottky barrier diode (SBD) fabricated by depositing Al-Foil on the p-type 4H-SiC substrate with a novel technology; DW. The electrical properties of physically fabricated Al-Foil/4H-SiC SBD have been investigated. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics based on the thermionic emission model in the temperature range (300 K–450 K) are investigated. It has been found that the ideality factor and barrier heights of identically manufactured Al-Foil/p-type-4H-SiC SBDs showing distinct deviation in their electrical characteristics. An improvement in the ideality factor of Al-Foil/p-type-4H-SiC SBD has been noticed with an increase in temperature. An increase in barrier height in fabricated SBD is also observed with an increase in temperature. We also found that these increases in barrier height, improve ideality factors and abnormalities in their electrical characteristics are due to structural defects initiation, discrete energy level formation, interfacial native oxide layer formation, inhomogenous doping profile distribution and tunneling current formation at the SiC sufaces.

Keywords

• <i>p</i>-type 4H-SiC
• diffusion welding
• inhomogeneity
• Schottky barrier diode
• barrier height
• ideality factor