Journal of Vacuum Science & Technology B, Vol.27, No.1, 476-481, 2009
Al2O3-SiO2 stack with enhanced reliability
The authors developed a new Al2O3-SiO2 (A-O) stack for application as a high voltage complementary metal oxide semiconductor (CMOS) dielectric and/or top oxide in electrically erasable programmable read only memory floating gate and polysilicon-oxide-nitride-oxide-silicon embedded memories in advanced technology nodes. An amorphous atomic layer deposited alumina is doped with nitrogen and transformed into the crystalline phase by further rapid thermal process annealing. The 65 angstrom effective oxide thickness (EOT) stack allows operating voltages twice exceeding the values for thermal SiO2 of the same EOT, has extremely low leakage currents, has negligible charge trapping, and is immune to degradation. Moreover, after alumina removal, the remaining strongly nitrided bottom oxide layer can be used as the gate dielectric of CMOS devices. (C) 2009 American Vacuum Society. [DOI: 10.1116/1.3025821]