A Highly Efficient Annealing Process With Supercritical N2O at 120 °C for SiO2/4H–SiC Interface

A novel post-oxidation annealing (POA) process with supercritical N
₂
O (SCN
₂
O) fluid is reported to be highly effective in improving the interface properties of the SiO
₂
/4H-silicon carbide (SiC) (0001) systems. After SCN
₂
O POA, the interface state density reduces to 2.8 ×10
¹¹
eV
^-1
cm
^-2
, which is about 3.5 times lower than that after a traditional high-temperature N
₂
O POA process. Meanwhile, the highest oxide critical electric field shows an increase of 18.19% and the near-interfacial oxide traps is reduced by 69.90% compared with that after N
₂
O POA process. The process temperature is as low as 120 °C. The significantly reduced processing temperature avoids additional defect generation while the supercritical state provides a stronger nitridation effect. SCN
₂
O annealing is a promising candidate for POA process toward high-performance SiC power metal-oxide-semiconductor field effect transistors (MOSFETs).