Chemical Vapor Deposition of Tungsten Schottky Diodes to 6H‐SiC

Abstract

Thermally stable tungsten Schottky contacts to low doped 6H‐silicon carbide (SiC) were fabricated via chemical vapor deposition at 670 K followed by a reactive ion etch to pattern the contacts. Physical characterization by x‐ray diffraction, x‐ray photoelectron spectroscopy, Rutherford backscattering spectrometry, and transmission electron microscopy verified a distinct W/6H‐SiC interface after a 2 h vacuum anneal at 1073 K. Current‐voltage (I‐V) and capacitance‐voltage (C‐V) measurements were performed at temperatures ranging from 295 to 773 K and revealed a low n‐type Schottky barrier Φ = 0.79 eV, ideal for low ohmic applications and a high p‐type Schottky barrier ΦBp 773 = 1.89 eV. At 473 K a current rectification ratio of 107 at ±10 V was observed for the p‐type contact.