Low-Energy Muons as a Tool for a Depth-Resolved Analysis of the SiO₂/4H-SiC Interface

Abstract

In this work, the potential of muon spin rotation (μSR) with low-energy muons (LE-μ) for the investigation of oxidation-induced defects at the SiO2/4H-SiC interface is explored. By using implantation energies for the muons in the keV range and comparing the fractions of muonium in different regions, the depth distribution of defects in the first 200 nm of the target material can be resolved. Defect profiles of interfaces with either deposited or thermally grown SiO2 layers on 4H-SiC are compared. The results show an increased number of defects in the case of a thermal oxide, both on the oxide and on the SiC side of the interface, with a spatial extension of a few tens of nm.

Characterization methods for defects and devices in silicon carbide

“…In the case of thermally oxidized SiC, the impact of oxidation-induced defects on the muonium forma-tion process has been shown. Depth profiles across the SiC/SiO 2 interface revealed an extended region of around 10 nm to 30 nm -both on the oxide and on the semiconductor side -with larger diamagnetic fraction 141 . For deposited oxides, on the other hand, no variation of F D near the interface is observed.…”