Charge-Trapping Characteristics of Ga2O3 Nanocrystals for Nonvolatile Memory Applications

Abstract

capacitors. The formation of Ga 2 O 3 NCs and their chemical bonding states were characterized by transmission electron microscopy and X-ray photoelectron spectroscopy. Compared with the device with Ga 2 O 3 NCs as chargetrapping layer, the one with nitrided Ga 2 O 3 NCs showed a larger memory window (4.7 V at ±10-V sweeping voltage), higher program speed (3.0 V at 100-μs +10 V), and data retention (charge loss of 27% at 125 • C), due to higher charge-trapping efficiency of the nitrided Ga 2 O 3 NCs and nitrogen-induced suppressed formation of interlayer at the Ga 2 O 3 /SiO 2 interface. Nanocrystal (NC)-based discrete-charge-storage nonvolatile memories have been considered as a promising candidate to replace the conventional floating-gate counterparts due to their stronger scaling ability, higher reliability, and lower program/erase (P/E) voltages. In this scope, many kinds of materials, such as Si, Ge, Pt, W, Ag and Au, have been proposed to act as NCs for memory applications. 1-4 Compared with semiconductor NCs (e.g. Si, Ge), the metal NCs have higher deep-level trap density around Femi level and a wider range of work function. 4,5 The main concerns for metal NCs lie in their poor thermal stability as well as incompatibility with metaloxide-semiconductor (MOS) process due to metal contamination. In addition, semiconducting oxide (e.g. ZnO) and conductive oxide (e.g. Indium Tin oxide) were also proposed as NCs due to their high work function and large band-gap. 6,7 The performance could be further improved by using dual-layer nanodot structure. 6,7 Owing to the conductive properties of metal and conductive oxide, well-separated NCs are required to suppress charge migration and charge leakage. Recently, metal-oxide dielectric nanocrystal memories (e.g. Gd 2 O 3 , Al 2 O 3 ) have attracted increasing interest because of their simple fabrication process, compatibility with MOS process, and high trap density. 5,8 Among various dielectrics, Ga 2 O 3 is well-known for its small bandgap (E g ∼ 4.4 eV versus 5.4 eV for Gd 2 O 3 , 8.8 eV for Al 2 O 3 ), thus leading to a larger barrier height between Ga 2 O 3 and the SiO 2 tunneling layer (TL). 9,10 Moreover, Ga 2 O 3 has a similar free energy of formation as SiO 2 (−998.3 kJ/mol versus −856.4 kJ/mol at 25 • C. −320.5 kJ/mol for ZnO; −520 kJ/mol for SnO 2 ; −1739.5 kJ/mol for Gd 2 O 3 ; −1582.3 kJ/mol for Al 2 O 3 ). 11 Consequently, a good Ga 2 O 3 /SiO 2 interface due to suppressed interfacial reaction can be also expected, which is desirable for good data retention of the memory device. 12 Nitrogen incorporation in dielectrics can also induce more deep traps, 13 and improve thermal stability and suppress elemental inter-diffusion. 10 Therefore, based on metalalumina-nitride-oxide-silicon (MANOS) capacitors, this work aims to study the charge-trapping characteristics of nitrided Ga 2 O 3 NC by comparison with that without nitrogen incorporation. ExperimentalMANOS capacitors with Al/Al 2 O 3 /Ga 2 O 3 NCs/SiO 2 /Si were fabricated on p-type silicon substrate. After a ...

Preparation and Catalytic Activity of Thermosensitive Ga2O3 Nanorods

“…For instance, the laser ablation method provides GaO­(OH) of spindle-like and nanofiber form, which produces Ga 2 O 3 nanorods upon dehydration . A combined procedure of laser ablation followed by reflux in the presence of cetyltrimethylammonium bromide or polyvinylpyrrolidone produces a mixture of GaO­(OH) and Ga 2 O 3 nanowires …”

“…11 A combined procedure of laser ablation followed by reflux in the presence of cetyltrimethylammonium bromide or polyvinylpyrrolidone produces a mixture of GaO(OH) and Ga 2 O 3 nanowires. 16 In the design of surface-exposed polymer−MO core−shell species, the core−shell must be easily accessed by the surrounding medium, a prerequisite for catalysis and sensing applications. 17−20 Stimuli-and thermoresponsive gallium-based oxides have been used as anchors for metal nanoparticles (NPs).…”

Effect of Annealing Atmosphere on the La2O3Nanocrystallite Based Charge Trap Memory

“…Numerous works have focused on developing charge trapping layers containing metallic or semiconducting NCs for use in nonvolatile memory devices [10][11][12][13][14][15][16][17]. However, researchers have been challenged by the poor thermal stability as well as the incompatibility with the metal oxide semiconductor (MOS) process of metallic or semiconducting NC memory devices [18,19].…”