Thermal oxidation of (0001) 4H-SiC at high temperatures in ozone-admixed oxygen gas ambient

Abstract

The method of oxidation by atomic oxygen has been developed for gate oxide formation in SiC metal–oxide–semiconductor (MOS) devices. Ozone (O3)–admixed oxygen (O2) gas is introduced into the cold-wall oxidation furnace, where atomic oxygen in a ground state is formed by thermal decomposition of O3 molecules at elevated sample temperatures. The growth rate of oxide in the O3-admixed gas shows a maximum at around 666.4 Pa and 950–1200 °C, whereas the rate in pure O2 gas is negligible below 6664.5 Pa. Interface trap density (Dit) of the MOS capacitors fabricated using atomic oxygen strongly depends on the oxidization temperature; oxidation at 1200 °C results in significant reduction of Dit in comparison with that at 950 °C.