First Principles Study of the Stability and Diffusion Mechanism of a Carbon Vacancy in the Vicinity of a SiO2/4H–SiC Interface. Issue 17 (12th August 2019)

• Record Type: Journal Article
• Authors: Alsnani, Hind; Goss, Jonathan P.; Briddon, Patrick; Rayson, Mark; Horsfall, Alton B.
• Other Names: Kissinger Gudrun guestEditor.; Kot Dawid guestEditor.; Richter Hans guestEditor.; Zöllner Marvin guestEditor.
• Is Part Of: Physica status solidi. Volume 216:Issue 17(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-08-12
• Subjects: 4H-SiC -- density-functional theory -- diffusion -- interfaces; Solid state physics -- Periodicals; Solids -- Industrial applications -- Periodicals; 530.41
• DOI: 10.1002/pssa.201900328
• Languages: English
• ISSNs: 1862-6300

Abstract

Abstract : The carbon vacancy in bulk 4H‐SiC and in the vicinity of an SiO2 /(0001)‐4H‐SiC interface using density‐functional theory is studied. It is found that the migration is hindered in the immediate vicinity of the interface, with the energy barrier for diffusion being ≈15% greater than the same defect in bulk 4H‐SiC. Herein, it is shown that the increased barrier is a consequence of the stabilization of the vacancy in the immediate interface due to a combination of strengthened reconstructions and interfacial relaxation, coupled with the destabilization of the transition‐state structure. Abstract : The majority of electronically active defects in SiC are located deep within the bandgap, thereby degrading the carrier transport properties of SiC. This study compares the diffusion of a carbon vacancy in different (0001)‐layers relative to a SiO2 /SiC interface using the density‐functional theory simulations. The results show that vacancies in the upper layers are stabilized due to stronger bonding and interfacial relaxation.