Abstract
Interfacial defects and electrical characteristics were analyzed to confirm the formation of dipole due to the densification of the SiO_2 buffer layer and the resulting movement of the flat-band voltage. Through the NAOS, the SiO_2 layer was densified without any change in thickness, and the suboxide density after the NAOS decreased from 2.23 × 10~(14) atoms/cm~2 (PE-CVD) to 1.33 × 10~(14) atoms/cm~2 (PE-CVD+NAOS). In addition, both electrical and interfacial defects decreased after NAOS and PMA. From these results, the SiO_2 buffer layer through the NAOS was densified and the interface defect state density was reduced. The PE-CVD sample with low atomic density had a dipole layer strength of 0.799 V before PMA, but it was 0.457 V in the case of PE-CVD+NAOS with high atomic density due to the densification of the SiO_2 buffer layer. Also, both samples were reduced to 0.488 V and 0.422 V after PMA. Based on this, the leakage current of PE-CVD was measured to be 3.05 × 10~(-5) A/cm~2, and the leakage current of PE-CVD+NAOS was measured that the difference in about four orders of magnitude was 1.64× 10~(-9) A/cm~2. Through the densification of the SiO_2 layer, the interface atomic density increased, and consequently, the dipole layer strength decreased, thereby improving the electrical properties.
NSTL
Elsevier