Effects of rapid thermal annealing on Al_2O_3/SiN reaction barrier layer/ thermal-nitrided SiO_2 stacking gate dielectrics on n-type 4H-SiC

摘要

In this letter, we have reported electrical and physical properties of rapid thermal annealed (RTA) Al_2O_3 stacking dielectric on n-type 4H-SiC. The effects of SiN-reaction barrier layer (RBL) between Al_2O_3 and thermal-nitrided SiO_2 on SiC-based metal-oxide-semiconductor characteristics have been investigated and compared. A significant reduction in oxide-semiconductor interface-trap density (D_(it)), improvement in dielectric breakdown field and reliability has been observed after the SiN-RBL has been introduced between Al_2O_3 and SiO_2. High-resolution transmission electron microscope and Auger electron spectroscopy analyses reveal that the SiN-RBL suppresses Al diffusion into the nitrided SiO_2 during RTA process.