Hafnium aluminum oxide as charge storage and blocking-oxide layers in SONOS-type nonvolatile memory for high-speed operation

Energy band alignments of Al2O3–HfO2/Al2O3 nanolaminates–SiO2–p-type Si structures

“…Various high-j dielectrics have been widely investigated as CTL, such as HfO 2 , HfAlO, ZrO 2 , and Y 2 O 3 . [4][5][6][7] In our research, we will investigate the memory characteristics of metal-Al 2 O 3 -high-j dielectric materials-SiO 2 -p-type Si (MAHOS) structures with aluminum as metal gate electrode, Al 2 O 3 as blocking oxide (BO), 1, 8 and HfO 2 /Al 2 O 3 nanolaminates (NL) as CTL.…”

Electrical Characteristics of Charge Trap Flash Memory with a Composition Modulated (ZrO2)x(Al2O3)1-xFilm

“…5(d) and (e). The crystallization of the film will generate grain boundaries, which can act as current leakage paths [18]. The excellent data retention characteristics of S1 should be attributed to the amorphous charge trapping layer [24] and variable potential barrier E B (0.8 to 1.6 eV), which suppress the leakage of trapped electrons toward the tunneling and blocking oxide.…”

“…In order to further improve memory characteristics and achieve the trade-off among the memory window, program/erase speed and data retention, extensive research has been carried out in recent years. This research has involved the use of nanocrystals (e.g., Ge [8], Si [9], Ni [10], and NiSi [11]), stacked structure [12][13][14], binary oxide dielectric film (e.g.,HfO 2 [15], GdO [16], and ZrO 2 [17]), and multiple oxide dielectric film [18,19] as a charge trapping layer. This work proposes a bandgap engineering technique using a composition modulated (ZrO 2 ) x (Al 2 O 3 ) 1-x film as the charge trapping layer in the CTFM device to improve the memory characteristics.…”

Correlation between charge trap distribution and memory characteristics in metal/oxide/nitride/oxide/silicon devices with two different blocking oxides, Al2O3 and SiO2

“…On the other hand, it appears that the ONO structure is not suitable for 10-year retention applications, because its charge decay rate is 0.15 V/decade, which is less than that of the ANO below 10 4 s. However, it increases rapidly to as high as 0.42 V/decade above 10 4 s. This kind of long-term retention problem has been pointed out in SONOS devices. 8,11 Because the charges are trapped efficiently at the deep trap centers, the ANO structure, having a larger trap density in the deep energy levels as well as a thicker blocking oxide, is thought to have better retention properties than ONO, especially in terms of the long-term stability. Moreover, it is important to reduce the interface traps between Si and SiO 2 , as much as possible, as observed in the ANO structure, because this could be a factor that can degrade the device reliability ͑or retention͒.…”