LaTiON/LaON as band-engineered charge-trapping layer for nonvolatile memory applications

Abstract

Charge-trapping characteristics of stacked LaTiON/LaON film were investigated based on Al/Al 2 O 3 / LaTiON-LaON/SiO 2 /Si (band-engineered MONOS) capacitors. The physical properties of the high-k films were analyzed by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. The band profile of this band-engineered MONOS device was characterized by investigating the current-conduction mechanism. By adopting stacked LaTiON/LaON film instead of LaON film as charge-trapping layer, improved electrical properties can be achieved in terms of larger memory window (5.4 V at ±10-V sweeping voltage), higher program speed with lower operating gate voltage (2.1 V at 100-µs +6 V), and smaller charge loss rate at 125°C, mainly due to the variable tunneling path of charge carriers under program/erase and retention modes (realized by the band-engineered chargetrapping layer), high trap density of LaTiON, and large barrier height at LaTiON/SiO 2 (2.3 eV).

Tunable bandgap energy of fluorinated nanocrystals for flash memory applications produced by low-damage plasma treatment

“…It has been used to improve the reliability of NC flash memory devices because it enables passivation of traps or defects using hydrogen atoms [16] (in the case of hydrogen plasma) or nitrogen atoms [17] (in the case of ammonia plasma). Gadolinium oxide (Gd 2 O 3 ), a rare-earth sesquioxide, has been reported to be a candidate as a gate dielectric for silicon and compound semiconductor device applications due to its low frequency dispersion, high k with high coupling ratio and process compatibility with easy fabrication for NCs formation [18][19][20]. The crystallized Gd 2 O 3 -NCs with low bandgap energy (E g ∼ 5.0-5.4 eV) surrounded by the high E g of amorphous Gd 2 O 3 dielectric (∼6.3-6.4 eV) to perform the energy band offset are responsible for the charge storage [21,22].…”

Advances in La-Based High-k Dielectrics for MOS Applications

“…Nb 2 O 5 , TiO 2 ), which is another way to increase the deep-level trap density in La 2 O 3 and suppress its reaction with the SiO 2 TL as well [84]; (iii) multi-CTL for band engineering, which is capable of enhancing charge-trapping efficiency [85] and improving device reliability by suppressing the impact of TL degradation [86]. Experimentally, these methods have all been studied, and the results in Figure 14 [61,84,[87][88][89][90] show obvious improvements in the performance of the memory device. HfLaO nanocrystal can provide the largest memory window, but the 50% degradation after 10 years in the retention property is not good for real applications.…”

“…CTM with La-based high-k CTL: (a) memory window, (b) P/E transient characteristics, and (c) retention property[61,84,[87][88][89][90].…”

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

“…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.…”