Time-dependent dielectric breakdown of gate oxide on 4H-SiC with different oxidation processes.

Effects of oxidation and nitric oxide (NO) post-oxidation annealing (POA) processes on the gate oxide integrity on 4H-SiC are investigated. Interface state density, flatband voltage, electron tunneling barrier height, breakdown field, and time-dependent dielectric breakdown are extracted. With the same NO POA condition, more nitrogen atoms are incorporated into wet oxide than dry oxide. The interface state density can be passivated effectively. At the same time, the electron tunneling barrier height at the SiO 2 /SiC interface approaches the ideal barrier height while positive charges would be introduced in oxide. NO annealing does not affect the breakdown field significantly. Regarding the time-dependent dielectric breakdown (TDDB) reliability, with increasing NO annealing time, the 10-year-projected intrinsic breakdown field decreases. It is concluded that NO annealing is effective in reducing the density of interface traps and hole traps originated from carboxyl defects, but excessive amount of nitrogen will turn into hole traps and thus deteriorates TDDB performance. • With the same NO POA condition, more nitrogen atoms are incorporated into wet oxide than dry oxide. • With nitrogen incorporation, the interface state density can be passivated effectively. • Wet oxidation results in slightly higher breakdown field while NO POA slightly reduces the breakdown field • With increasing NO annealing time, the 10-year-projected intrinsic breakdown field decreases for both wet and dry oxidation samples. • Excessive amount of nitrogen will turn into hole traps and thus deteriorates TDDB reliability of gate oxide on 4H-SiC. [ABSTRACT FROM AUTHOR]