Highly reliable M1X MLC NAND flash memory cell with novel active air-gap and p+ poly process integration technologies
Jihyun Seo, Kyoung-Rok Han, Tae-Un Youn, Hye-Eun Heo, Sang-Hyun Jang, Jongwook Kim, Ho-Nam Yoo, Joowon Hwang, Cheol‐Hoon Yang, Heeyoul Lee, Byungkook Kim, Eun-Seok Choi, Keum-Hwan Noh, Byoungki Lee, Byungseok Lee, Heehyun Chang, Sung-Kye Park, Kun-Ok Ahn, Seokkiu Lee, Jinwoong Kim · 2013
Our Middle-1X nm MLC NAND (M1X) flash cell is intensively characterized with respect to reliability and manufacturability. For the first time, the novel active air-gap technology is applied to alleviate the drop of channel boosting potential of program inhibition mode, BL-BL interference is reduced to our 2y nm node level by this novel integration technology. Furthermore, it also relaxes the effect of process variation like EFH (Effective Field oxide Height) on cell Vt distribution. Better endurance and retention characteristics can be obtained by p+ doped poly gate. By optimization of active air-gap profile and poly doping level, M1X nm MLC NAND flash memory has been successfully implemented with superior manufacturability and acceptable reliability.