Improvement in Thermal Stability of Stacked Structures of Aluminum Nitride and Lanthanum Oxide Thin Films on Si Substrate

No, Sang Yong; Park, Heechul; Hwang, Cheol Seong; Kim, Hyeong Joon

doi:10.1149/1.2787837

Cited by 10 publications

(8 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Rare-earth oxide is known to actively react with OH due to its hydration characteristics. 20 Fig . 2a shows the current-voltage (I-V) characteristics of the fabricated Al/Yb 2 O 3 /TaN ReRAM cell before and after electro-forming process.…”

Section: Methodsmentioning

confidence: 99%

The Effect of Al and Ni Top Electrodes in Resistive Switching Behaviors of Yb2O3-Based Memory Cells

Mondal

Her

et al. 2012

ECS Solid State Letters

View full text Add to dashboard Cite

In this letter, the effect of Al and Ni top electrodes in resistive switching behavior of Al/Yb 2 O 3 /TaN and Ni/Yb 2 O 3 /TaN memory devices is proposed. The Al/Yb 2 O 3 /TaN memory device demonstrates no such switching performance as applying bias on both top and bottom electrodes, whereas the Ni/Yb 2 O 3 /TaN reveals the bipolar memory switching behavior with a high resistance ratio of 10 4 for over 200 cycles of switching responses and good data retention with memory window of about 10 5 at 85 • C, as extrapolated up to 10 years. The resistance switching dynamic is ascribed to the conductivity modulation by oxygen ions/vacancies controlled electrochemical reaction process in the Yb 2 O 3 switching layer.Resistive random access memory (ReRAM) is an emerging storage device for next generation high potential nonvolatile memory (NVM) applications due to its scaling ability, low cost, and compatibility of being integrated in back-end-of-line (BEOL) process in complementary metal-oxide-semiconductor (CMOS) fabrication. 1-7 A simple ReRAM device structure usually consists of an oxide layer sandwiched between two metal electrodes. Application of low voltage electrical pulse with certain level can change the oxide's resistance significantly between two stable states, namely high resistance state (HRS) and low resistance state (LRS). Nonvolatile resistive switching behavior has been demonstrated for several binary oxides, including . 8-13 Although resistance-switching phenomena in several binary metal oxides have been known from decades, the details of the switching mechanisms and the nature of the different resistive states are still under debate. Different switching models such as domain and tunneling model, 14 filament model, 15,16 and field induced crystallinity and charge trapping model [17][18][19] have been studied extensively. However, exact switching phenomena are not clearly understood yet. In this letter, we explored an improved resistive switching behavior of Ni/Yb 2 O 3 /TaN memory cells in compare with Pt/Yb 2 O 3 /TiN memory cell. 13 Additionally, the influence of top electrode material (Ni and Al) on the electrical properties of Yb 2 O 3 -based ReRAM is discussed to realize for next generation universal memory application.It is found that the bipolar resistive switching behavior in Ni/Yb 2 O 3 /TaN ReRAM cell keeps stable resistance ratio of 10 4 with switching responses over 200 cycles. Good data retention for 10 5 s with sufficient memory window at 85 • C is also demonstrated. The resistance switching dynamic is attributed to the filamentary conduction of oxygen ions/vacancies by electrochemical reaction process in the Yb 2 O 3 switching layer. ExperimentalThe TaN bottom electrode was deposited on SiO 2 /Si substrates by sputter deposition technique. Then, a 30-nm Yb 2 O 3 thin film was deposited on the TaN by radio frequency (rf) magnetron sputtering with an Ar/O 2 atmosphere using a metallic Yb target. The chamber working pressure was maintained at 10 −2 Torr, while the Ar/O 2 flow was set at 3:1 p...

show abstract

Section: Methodsmentioning

confidence: 99%

The Effect of Al and Ni Top Electrodes in Resistive Switching Behaviors of Yb2O3-Based Memory Cells

Mondal

Her

et al. 2012

ECS Solid State Letters

View full text Add to dashboard Cite

show abstract

“…The diffusion of the Si atoms and interface layer formation are accompanied by the diffusion of O atoms from the residual gas in the RTA chamber. 10,11 In Fig. 1a, the O peak area of annealed film was increased remarkably compared with that of the as-deposited film.…”

mentioning

confidence: 93%

“…The authors also reported a loss of interfacial Al atoms, which had been interposed between the La 2 O 3 layer and Si substrate. 10 Moreover, an Al-rich surface layer was obtained from the La 2 O 3 /Al͑O,N͒/Si structure after thermal annealing at 800°C. 10 It was suggested that the migration of Al atoms to the surface is related to interface layer formation.…”

mentioning

confidence: 99%

“…10 Moreover, an Al-rich surface layer was obtained from the La 2 O 3 /Al͑O,N͒/Si structure after thermal annealing at 800°C. 10 It was suggested that the migration of Al atoms to the surface is related to interface layer formation. In order to adopt LaAlO 3 films as a gate oxide, studies on changes in film/substrate structure and the stoichiometry of LaAlO 3 films at high temperatures are essential.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Thermal Annealing Effects on the Atomic Layer Deposited LaAlO[sub 3] Thin Films on Si Substrate

Hwang

Kim

Cho

et al. 2008

Electrochem. Solid-State Lett.

Self Cite

View full text Add to dashboard Cite

The changes in film structure of amorphous atomic layer deposited LaAlO 3 thin films after thermal annealing were examined by medium-energy ion-scattering measurements and angle-resolved X-ray photoelectron spectroscopy. Thermal annealing induces Si-rich LaSiO and Al-deficient LaAl x Si y O z layers on a few monolayers of SiO 2 . Al atoms do not participate in silicate formation during annealing. Instead, they migrate toward the film surface, which induces nonhomogeneity in the films along the vertical direction. The concentrations of Al and La on the film surface increase and decrease, respectively, as a result of Si diffusion from the substrate and silicate formation.LaAlO 3 is a promising gate dielectric material in future complementary metal-oxide-semiconductor devices on account of its larger bandgap ͑ϳ6.2 eV͒ and comparable dielectric constant ͑24-27͒ compared with HfO 2 . 1,2 It is also thermodynamically stable on Si substrates. 3,4 It was reported that as-deposited amorphous LaAlO 3 films on Si by molecular-beam deposition do not exhibit any SiO 2 or silicate interface layer. 4 Moreover, epitaxial Si films maintain an abrupt interface with LaAlO 3 substrates even after annealing at 900°C. 3 However, the interfacial stability of LaAlO 3 /Si varies according to the types of deposition techniques used for LaAlO 3 growth. In many cases, inevitable interface layer formation between the amorphous LaAlO 3 thin films and Si substrate during film deposition and postdeposition annealing ͑PDA͒ have been reported. 1,2,5-9 Interface layer formation normally has an adverse effect on the device performance. In this study, the equivalent oxide thickness of a LaAlO 3 film increased from 2.23 to 2.46 nm after PDA at 800°C. However, the mechanisms for the interfacial reaction between the LaAlO 3 thin films and Si substrate during film deposition and PDA are not completely understood. Previous studies using angleresolved X-ray photoelectron spectroscopy ͑ARXPS͒ 1 and secondary ion mass spectroscopy 2 reported that Al-deficient interfacial La x Al y O z Si layers are formed during film growth. The authors also reported a loss of interfacial Al atoms, which had been interposed between the La 2 O 3 layer and Si substrate. 10 Moreover, an Al-rich surface layer was obtained from the La 2 O 3 /Al͑O,N͒/Si structure after thermal annealing at 800°C. 10 It was suggested that the migration of Al atoms to the surface is related to interface layer formation. In order to adopt LaAlO 3 films as a gate oxide, studies on changes in film/substrate structure and the stoichiometry of LaAlO 3 films at high temperatures are essential.In this study, 5-6 nm thick LaAlO 3 thin films were deposited on Si substrates by the sequential deposition of La 2 O 3 and Al 2 O 3 submonolayers in an atomic layer deposition ͑ALD͒ manner. The LaAlO 3 films were annealed by rapid thermal annealing ͑RTA͒ and the structural variations were investigated.An alternating layer of La 2 O 3 and Al 2 O 3 thin films were deposited on a p-type Si͑100͒ wafer to form a LaAlO 3...

show abstract

“…1 However, atomic layer deposition (ALD) of La-containing films has several challenges such as the limited selection of precursors and inducement of unstable film growth due to its hygroscopic behavior. 3 Additionally, serious Si diffusion from the substrate into the La 2 O 3 film during deposition have been reported. 4,5 The use of Si-containing Tris[bis(trimethylsilyl)amino]lanthanum, La[N(SiMe 3 ) 2 ] 3 , as a La precursor was reported as the promising way to intentionally incorporate Si in La 2 O 3 film to prevent the diffusion of Si from Si substrates.…”

mentioning

confidence: 99%

Effects of Oxygen Source on Film Properties of Atomic-Layer-Deposited La-Silicate Film Using La[N(SiMe3)2]3

Choi

Won

Jung

et al. 2012

ECS Solid State Letters

View full text Add to dashboard Cite

The effect of oxygen sources, i.e. O 3 or H 2 O, on chemical composition, dielectric constant and leakage current density of atomiclayer-deposited La-silicate films was examined. The dielectric constant of La-silicate films grown using O 3 was ∼8.0, which was lower than that of La-silicate films grown using H 2 O, ∼11.7 due to the higher Si concentrations. However, leakage current density of La-silicate films grown using O 3 was about 3 orders of magnitude lower than that of La-silicate films grown using H 2 O at an identical capacitance-equivalent-thickness (but almost half the physical thickness), due to the higher Si concentrations and less La-carbonate formation.As the next generation high-k dielectric film as well as the threshold voltage control layer, La 2 O 3 film are attracting much attention nowadays due to their high dielectric constant (∼30) 1,2 and large conduction band offset (CBO) with Si (∼2.3 eV). 1 However, atomic layer deposition (ALD) of La-containing films has several challenges such as the limited selection of precursors and inducement of unstable film growth due to its hygroscopic behavior. 3 Additionally, serious Si diffusion from the substrate into the La 2 O 3 film during deposition have been reported. 4,5 The use of Si-containing Tris[bis(trimethylsilyl)amino]lanthanum, La[N(SiMe 3 ) 2 ] 3 , as a La precursor was reported as the promising way to intentionally incorporate Si in La 2 O 3 film to prevent the diffusion of Si from Si substrates. 6 Since, significant Si diffusion during ALD of La 2 O 3 film and post-deposition annealing degrades the gate controllability by increasing permittivity of the gate oxide film, the use of Lasilicate film instead of La 2 O 3 film is more attractive. Even though the chemical properties of ALD La-silicate films using La[N(SiMe 3 ) 2 ] 3 and H 2 O were reported, 6-9 a systematic study on the influence of the type of oxygen source, H 2 O or O 3 , on the growth behavior and electrical properties of La-silicate films using La[N(SiMe 3 ) 2 ] 3 has been rarely reported. 10 In this study, the ALD behavior and electrical properties of La-silicate films according to the type of oxygen source were examined. In particular, the changes in Si concentration of the ALD La-silicate film grown using the La[N(SiMe 3 ) 2 ] 3 precursor were focused.La-silicate films were grown on a HF-cleaned p-type (100) Si substrate at a wafer temperature of 310 • C in a traveling-wave type 4-in. thermal ALD reactor with a liquid delivery system using La[N(SiMe 3 ) 2 ] 3 as the metal precursor. O 3 of 110 g/Nm 3 and H 2 O at room temperature were used as the oxygen sources for O 3 -La-silicate and H 2 O-La-silicate films, respectively. La[N(SiMe 3 ) 2 ] 3 was vaporized at 190 • C and delivered to the reactor in the Ar carrier gas of 200 sccm. The injection time of La[N(SiMe 3 ) 2 ] 3 dissolved in hexane was controlled in milliseconds to precisely deliver it to a vaporizer. The injection time for La source, H 2 O and O 3 was fixed at 0.1ms, 1s and 5s, respectively. The base pressure of th...

show abstract

Improvement in Thermal Stability of Stacked Structures of Aluminum Nitride and Lanthanum Oxide Thin Films on Si Substrate

Cited by 10 publications

References 17 publications

The Effect of Al and Ni Top Electrodes in Resistive Switching Behaviors of Yb2O3-Based Memory Cells

The Effect of Al and Ni Top Electrodes in Resistive Switching Behaviors of Yb2O3-Based Memory Cells

Thermal Annealing Effects on the Atomic Layer Deposited LaAlO[sub 3] Thin Films on Si Substrate

Effects of Oxygen Source on Film Properties of Atomic-Layer-Deposited La-Silicate Film Using La[N(SiMe3)2]3

Contact Info

Product

Resources

About