This paper compares the behavior of the gate oxide in 4H-SiC lateral MOSFETs subjected to post-deposition annealing (PDA) in N2O and POCl3. A significantly higher channel mobility was measured in 4H-SiC MOSFETs subjected to PDA in POCl3 (108 cm2 V−1 s−1) with respect to N2O (19 cm2 V−1 s−1), accompanying a reduction of the interface traps density. Hence, a different temperature coefficient of the mobility and of the threshold voltage was observed in the two cases. According to structural analysis, the gate oxide subjected to PDA in POCl3 showed a different surface morphology than that treated in N2O, as a consequence of the strong incorporation of phosphorous inside the SiO2 matrix during annealing. This latter explained the instability of the electrical behavior of MOS capacitors annealed in POCl3.
Springer Berlin Heidelberg
1 Apr 2014
Volume: 115 Issue: 1 Pages: 333-339
Applied Physics A