Study of Photo-Induced Effect in Obliquely-Deposited Amorphous Ge-Se Films by XPS

Ueno, Tokihiro; Odajima, Akira

doi:10.1143/jjap.19.l519

Cited by 12 publications

(4 citation statements)

References 9 publications

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“…The peak binding energies of Ge 0.5 Se 0.5 , Ge 0.4 Se 0.6 , Ge 0.3 Se 0.7 , and Ge 0.2 Se 0.8 films are found to be 30.1, 30.6, 31, and 31.1 eV, respectively. The peak binding energy of Ge 3d electrons increased (30.1 to 31.1 = 1 eV) owing to increased Se content [34,35]. The chemical shifts of Ge 3d (29 eV) electrons are 1.1, 1.6, 2.0, and 2.1 eV for Ge 0.5 Se 0.5 , Ge 0.4 Se 0.6 , Ge 0.3 Se 0.7 , and Ge 0.2 Se 0.8 films, respectively.…”

Section: Materials and Deposition Methodsmentioning

confidence: 99%

Conductive-bridging random access memory: challenges and opportunity for 3D architecture

Jana¹,

Roy²,

Panja³

et al. 2016

Nano Online

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The performances of conductive-bridging random access memory (CBRAM) have been reviewed for different switching materials such as chalcogenides, oxides, and bilayers in different structures. The structure consists of an inert electrode and one oxidized electrode of copper (Cu) or silver (Ag). The switching mechanism is the formation/dissolution of a metallic filament in the switching materials under external bias. However, the growth dynamics of the metallic filament in different switching materials are still debated. All CBRAM devices are switching under an operation current of 0.1 μA to 1 mA, and an operation voltage of ±2 V is also needed. The device can reach a low current of 5 pA; however, current compliance-dependent reliability is a challenging issue. Although a chalcogenide-based material has opportunity to have better endurance as compared to an oxide-based material, data retention and integration with the complementary metal-oxide-semiconductor (CMOS) process are also issues. Devices with bilayer switching materials show better resistive switching characteristics as compared to those with a single switching layer, especially a program/erase endurance of >10 5 cycles with a high speed of few nanoseconds. Multi-level cell operation is possible, but the stability of the high resistance state is also an important reliability concern. These devices show a good data retention of >10 5 s at >85°C. However, more study is needed to achieve a 10-year guarantee of data retention for non-volatile memory application. The crossbar memory is benefited for high density with low power operation. Some CBRAM devices as a chip have been reported for proto-typical production. This review shows that operation current should be optimized for few microamperes with a maintaining speed of few nanoseconds, which will have challenges and also opportunities for three-dimensional (3D) architecture.

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Section: Materials and Deposition Methodsmentioning

confidence: 99%

Conductive-bridging random access memory: challenges and opportunity for 3D architecture

Jana¹,

Roy²,

Panja³

et al. 2016

Nano Online

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show abstract

“…Figure 1a shows the XPS spectra of Ge 3 d core-level electrons. In the case of the Ge 0.5 Se 0.5 /W samples, the peak binding energy of Ge 3 d core-level electrons was 30.1 eV, higher than that of the pure Ge 3 d peak (29 eV) [39]. This suggests that the Ge 3 d peak centered at 30.1 eV represents the GeSe composition.…”

Section: Methodsmentioning

confidence: 99%

“…The peak binding energy of GeSe 2 is 54.7 eV, and the corresponding binding energy of Se 3 d core-level electrons in the Ge 0.2 Se 0.8 film is approximately 54.8 eV. However, the chemical shift of Se 3 d (55.5 eV) electrons is −1 eV for GeSe 2 [39]. The increase in binding energy with increasing Se content allows us to confirm the higher Se content in the GeSe x film [39,40].…”

Section: Methodsmentioning

confidence: 99%

Enhanced nanoscale resistive switching memory characteristics and switching mechanism using high-Ge-content Ge0.5Se0.5 solid electrolyte

et al. 2012

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We demonstrate enhanced repeatable nanoscale bipolar resistive switching memory characteristics in Al/Cu/Ge0.5Se0.5/W, as compared with Al/Cu/Ge0.2Se0.8/W structures, including stable AC endurance (>105 cycles), larger average SET voltage (approximately 0.6 V), excellent data retention (>105 s) at 85°C, and a high resistance ratio (>104) with a current compliance of 8 μA and a small operation voltage of ±1.5 V. A small device size of 150 × 150 nm2 and a Cu nanofilament with a small diameter of 30 nm are both observed by high-resolution transmission electron microscope in the SET state. The GexSe1 − x solid electrolyte compositions are confirmed by both energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The switching mechanism relies on the smaller barrier heights for holes rather than for electrons; the positively charged Cuz+ ions (i.e., holes) migrate through the defects in the GexSe1 − x solid electrolytes during SET/RESET operations. Hence, the Cu nanofilament starts to grow at the Ge0.5Se0.5/W interface, and starts to dissolve at the Cu/Ge0.5Se0.5 interface, as illustrated in the energy band diagrams. Owing to both the higher barrier for hole injection at the Cu/Ge0.5Se0.5 interface than at the Cu/Ge0.2Se0.8 interface and greater thermal stability, the resistive switching memory characteristics of the Al/Cu/Ge0.5Se0.5/W are improved relative to the Al/Cu/Ge0.2Se0.8/W devices. The Al/Cu/Ge0.5Se0.5/W memory device can also be operated with a low current compliance of 1 nA, and hence, a low SET/RESET power of 0.61 nW/6.4 pW is achieved. In addition, a large memory size of 1,300 Pbit/in2 is achieved with a small nanofilament diameter of 0.25 Å for a small current compliance of 1 nA.

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“…The peak binding energies of Ge 0.5 Se 0.5 , Ge 0.4 Se 0.6 , Ge 0.3 Se 0.7 , and Ge 0.2 Se 0.8 films are found to be 30.1, 30.6, 31, and 31.1 eV, respectively. The peak binding energy of Ge 3d electrons increased (30.1 to 31.1 = 1 eV) owing to increased Se content [ 34 , 35 ]. The chemical shifts of Ge 3d (29 eV) electrons are 1.1, 1.6, 2.0, and 2.1 eV for Ge 0.5 Se 0.5 , Ge 0.4 Se 0.6 , Ge 0.3 Se 0.7 , and Ge 0.2 Se 0.8 films, respectively.…”

Section: Reviewmentioning

confidence: 99%

Conductive-bridging random access memory: challenges and opportunity for 3D architecture

et al. 2015

View full text Add to dashboard Cite

The performances of conductive-bridging random access memory (CBRAM) have been reviewed for different switching materials such as chalcogenides, oxides, and bilayers in different structures. The structure consists of an inert electrode and one oxidized electrode of copper (Cu) or silver (Ag). The switching mechanism is the formation/dissolution of a metallic filament in the switching materials under external bias. However, the growth dynamics of the metallic filament in different switching materials are still debated. All CBRAM devices are switching under an operation current of 0.1 μA to 1 mA, and an operation voltage of ±2 V is also needed. The device can reach a low current of 5 pA; however, current compliance-dependent reliability is a challenging issue. Although a chalcogenide-based material has opportunity to have better endurance as compared to an oxide-based material, data retention and integration with the complementary metal-oxide-semiconductor (CMOS) process are also issues. Devices with bilayer switching materials show better resistive switching characteristics as compared to those with a single switching layer, especially a program/erase endurance of >105 cycles with a high speed of few nanoseconds. Multi-level cell operation is possible, but the stability of the high resistance state is also an important reliability concern. These devices show a good data retention of >105 s at >85°C. However, more study is needed to achieve a 10-year guarantee of data retention for non-volatile memory application. The crossbar memory is benefited for high density with low power operation. Some CBRAM devices as a chip have been reported for proto-typical production. This review shows that operation current should be optimized for few microamperes with a maintaining speed of few nanoseconds, which will have challenges and also opportunities for three-dimensional (3D) architecture.

show abstract

Study of Photo-Induced Effect in Obliquely-Deposited Amorphous Ge-Se Films by XPS

Cited by 12 publications

References 9 publications

Conductive-bridging random access memory: challenges and opportunity for 3D architecture

Conductive-bridging random access memory: challenges and opportunity for 3D architecture

Enhanced nanoscale resistive switching memory characteristics and switching mechanism using high-Ge-content Ge0.5Se0.5 solid electrolyte

Conductive-bridging random access memory: challenges and opportunity for 3D architecture

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