Gadolinium oxide nanocrystal nonvolatile memory with HfO2/Al2O3 nanostructure tunneling layers

Abstract

In this study, Gd2O3 nanocrystal (Gd2O3-NC) memories with nanostructure tunneling layers are fabricated to examine their performance. A higher programming speed for Gd2O3-NC memories with nanostructure tunneling layers is obtained when compared with that of memories using a single tunneling layer. A longer data retention (< 15% charge loss after 104 s) is also observed. This is due to the increased physical thickness of the nanostructure tunneling layer. The activation energy of charge loss at different temperatures is estimated. The higher activation energy value (0.13 to 0.17 eV) observed at the initial charge loss stage is attributed to the thermionic emission mechanism, while the lower one (0.07 to 0.08 eV) observed at the later charge loss stage is attributed to the direct tunneling mechanism. Gd2O3-NC memories with nanostructure tunneling layers can be operated without degradation over several operation cycles. Such NC structures could potentially be used in future nonvolatile memory applications.

Theoretical Analysis and Characterization of Multi-Islands Single-Electron Devices with Applications

“…At the beginning, NAND flash memories with just stacked structures of the conventional planar-type device with single NC or poly-NCs channels were considered [17, 18]. Then, they have been advanced to reduce the process cost further with unique 2D array architecture of metallic NCs [19, 20]. …”

Recent Progress of Rare Earth Oxides for Sensor, Detector, and Electronic Device Applications: A Review

“…The nanostructure tunneling layer and high programming speed of Gd 2 O 3 nanocrystals (Gd 2 O 3 –NC) are acquired when contrasted with that of memories utilizing a monotunneling layer. Moreover, the device made by Gd 2 O 3 –NC also demonstrated longer memory retention where less than 15% charge loss is observed after 10 4 s. The expanded physical thickness of the tunneling layer made it possible, demonstrated in Figure . On the other hand, 900 °C was the ideal condition for the annealing temperature to deduce the interface traps and defects and , consequently, upgrade material characteristics to manufacture a well-qualified crystalline film .…”

“…The optoelectrical properties of sesquioxide-synthesized nanocomposites are, therefore, a remarkable addition in novel humidity sensors − for ambient humidity monitoring. The nanocrystalline structures and high photoluminescence properties have enhanced the use of R 2 O 3 -synthesized nanoparticles as an attractive material in novel biosensing applications of the medical sector. ,− Their unique traits have also been employed in a wide variety of industrial and consumer electronic device applications encompassing memory devices, ,− metal oxide semiconductors (MOSs), ,,, dielectric material devices, − highly efficient capacitors, − to energy storage devices. , The high dielectric constant, thermodynamic strength, high band energy gap, sputtering power, high power density, and longevity have immensely favored REOs as a suitable dopant for various electronic devices. ,, …”

Thickness dependence of Al2O3/HfO2/Al2O3 stacked tunneling layers on gadolinium oxide nanocrystal nonvolatile memory

“…The CF 4 plasma treatment for a long time with significant plasma damage will degrade the memory performance. In addition, the memories with hybrid Gd 2 O 3 nanocrystal and charge trapping layer have been realized by using a thick Gd 2 O 3 layer [18]. Though the memories with thick Gd 2 O 3 layer presented enhanced memory characteristics, the endurance property was found to be degraded due to the charge trapping issue.…”

“…Furthermore, the gadolinium oxide (Gd 2 O 3 ) nanocrystal, a rare earth metal oxide material, has been proposed to exhibit superior memory properties [14][15][16][17][18][19]. The Gd 2 O 3 -NCs can be formed by the crystallized Gd 2 O 3 dots with small band-gap surrounded by the amorphous Gd 2 O 3 film with large band-gap [20], which is different from the traditional NCs embedded in SiO 2 matrix [6,[11][12][13].…”