Characterization of SiO2/SiC Interfaces Annealed in N2O or POCl3

This paper reports a comparative characterization of SiO2/SiC interfaces subjected to post-oxide-deposition annealing in N2O or POCl3. Annealing process of the gate oxide in POCl3 allowed to achieve a notable increase of the MOSFET channel mobility (up to 108 cm2V-1s-1) with respect to the N2O annealing (about 20 cm2V-1s-1), accompanied by a different temperature behaviour of the electrical parameters in the two cases. Structural and compositional analyses revealed a different surface morphology of the oxide treated in POCl3, as a consequence of the strong incorporation of phosphorous inside the SiO2 matrix during annealing. This latter explained the instability of the electrical behaviour of MOS capacitors annealed in POCl3.