Reduction of charge-transport characteristics of SiGe dot floating gate memory device with ZrO/sub 2/ tunneling oxide

Abstract

We have demonstrated the effects of charging voltage and the charge retention characteristics in silicon-germanium dots with ZrO/sub 2/ tunneling oxide. Using the ZrO/sub 2/ high-k dielectric tunneling oxide, we achieved a low write voltage and improved retention time as compared to the SiGe dots with a SiO/sub 2/ tunneling oxide. The discharge behavior of the ZrO/sub 2/ device is similar to that of Si dots embedded in SiO/sub 2/ in terms of a logarithmic charge decay. This demonstrates that the SiGe dots with ZrO/sub 2/ tunneling oxide can be used to replace SiGe dots with SiO/sub 2/ tunneling oxide as the floating gate in EEPROMs and have a high potential for further scaling of floating-gate memory devices.