Comment on "Catastrophic degradation of the interface of epitaxial silicon carbide on silicon at high temperatures" [Appl. Phys. Lett. 109, 011604 (2016)]

Abstract

The authors of a recently published letter1 state the purpose of their work as an evaluation of the stability of SiC/Si hetero-junctions at high temperatures. The central finding is that temperature annealing at 1100 °C leads to “catastrophic degradation” of “the diode behaviour of the initial p-Si/n-SiC junction.” The key electrical measurements that underpin these statements were performed on in-house SiC films,2 grown at 1000 °C on p-type Si substrates. The measurements were performed on bare Si samples and on n-SiC/p-Si samples before and after annealing. It was found that the 1100 °C annealing changes the initially measured n-type conduction, with a sheet resistance of RSiC=1354 Ω/□, to p-type conduction and a very small sheet resistance of 24 Ω/□. This change from 1354 Ω/□ (n type) before the annealing to only 24 Ω/□ (p type) after the annealing is the basis for the central statement of “catastrophic degradation,” which is specified as “shorting of the SiC film to the substrate upon annealing with consequent dominance of the carriers in the thick silicon substrate, with relatively high mobility.”