Title :
Improvement of Memory State Misidentification Caused by Trap-Assisted GIDL Current in a SONOS-TFT Memory Device
Author :
Chen, Te-Chih ; Chang, Ting-Chang ; Jian, Fu-Yen ; Chen, Shih-Ching ; Lin, Chia-Sheng ; Lee, Ming-Hsien ; Chen, Jim-Shone ; Shih, Ching-Chieh
Author_Institution :
Dept. of Phys., Nat. Sun Yat-Sen Univ., Kaohsiung, Taiwan
Abstract :
This letter studies the nonvolatile memory characteristics of polycrystalline-silicon thin-film transistors with a silicon-oxide-nitride-oxide-silicon (SONOS) structure. As the device was programmed, significant trap-assisted gate-induced drain leakage current was observed due to the extra programmed electrons trapped in the nitride layer which lies above the gate-to-drain overlap region. In order to suppress the leakage current and thereby avoid signal misidentification, we utilized band-to-band hot hole injection into the nitride layer. Because the injected hot holes can remain in the nitride layer after repeated Fowler-Nordheim erase and program operations, this method can exhibit good sustainability in such a SONOS-TFT memory device.
Keywords :
leakage currents; random-access storage; silicon; thin film transistors; SONOS-TFT memory device; Si; band-to-band hot hole injection; extra programmed trapped electrons; gate-to-drain overlap; memory state misidentification; nitride layer; nonvolatile memory; polycrystalline-silicon thin-film transistors; program operation; repeated Fowler-Nordheim erase operation; signal misidentification; silicon-oxide-nitride-oxide-silicon structure; trap-assisted GIDL current; trap-assisted gate-induced drain leakage current; Memories; thin film transistors;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2009.2023827
