Fabrication and electrical characterization of MONOS memory with novel high- k gate stack

A novel high-κ gate stack structure with HfON/SiO₂ as dual tunneling layer (DTL), AlN as charge storage layer (CSL) and HfAlO as blocking layer (BL) is proposed to prepare the charge-trapping type of MONOS non-volatile memory device by employing in-situ sputtering method. The memory window, program/erase and retention properties are investigated and compared with similar gate stack structure with Si₃N₄/SiO₂ as DTL, HfO₂ as CSL and Al₂O₃ as BL. Results show a large memory window of 3.55 V at P/E voltage of +8 V/-15 V, high program/erase speed and good retention characteristic can be achieved using the novel Au/ HfAlO/AlN/(HfON/SiO₂)/Si gate stack structure. The main mechanisms lie in the enhanced electron injection through the high-κ HfON/SiO₂ DTL, high trapping efficiency of the high-κ AlN material and effective blocking role of the high-κ HfAlO BL.