Comparison of Fluorinated HfO^sub 2^ and Si^sub 3^N^sub 4^ Charge Trapping Layer for Nonvolatile Flash Memories

• Published in: Ferroelectrics 2012-01, Vol.435 (1), p.38
• Main Authors: Chen, Yung-Yu, Lei, Gen, Shen, Yu-Jie, Lin, Shin-Chieh, Chen, Yih-Chien
• Format: Article
• Language: English
• Subjects: Comparative analysis; Computer memory; Dielectric properties; Electric fields
• ISSN: 0015-0193; 1563-5112

Characteristics of fluorinated metal/... (F-MOHOS) and fluorinated metal/... (F-MONOS) flash memory using gate fluorine ion implantation (GFI) have been investigated. Since dielectric constant of HfO2 is larger than ..., electric field across on tunneling oxide of F-MOHOS flash memory is larger than F-MONOS flash memory, which results in faster program/erase speed. Moreover, HfO2 exhibits larger effective trapping density than Si3N4, which also contributes to faster program/erase speed for the F-MOHOS flash memory. Besides, charge retention of the F-MOHOS flash memory is superior than the F-MONOS flash memory, primarily due to larger conduction band offset at the HfO2/SiO2 interface (...EC = 1.7-2.0 eV) than at the Si3N4/SiO2 interface (...EC = 1.1 eV). F-MOHOS flash memory also exhibits superior program/erase endurance than F-MONOS flash memory. Therefore, F-MOHOS flash memory using GFI process is proposed to be suitable for future nonvolatile flash memory applications. On the other hand, larger dielectric constant of HfO2 inevitably induces larger electric field across on blocking oxide of F-MOHOS flash memory, then enhances electron back-tunneling from the gate electrode during erase operation, which results in obvious erase-saturation. (ProQuest: ... denotes formulae/symbols omitted.)