Impact of carbon and nitrogen impurities in high-κ dielectrics on metal-oxide-semiconductor devices

Choi, Minseok; Lyons, John L.; Janotti, Anderson; Walle, Chris G. Van de

doi:10.1063/1.4801497

Cited by 102 publications

(100 citation statements)

References 29 publications

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“…35 The low N and C levels obtained are a clear merit, as in earlier work the performance of devices with HfO 2 has clearly shown to degrade with increasing impurity levels. 30,31 Moreover, as will be shown in Sec. III B, the degree of crystallinity increases for higher deposition temperatures.…”

Section: Resultsmentioning

confidence: 59%

Atomic layer deposition of HfO2 using HfCp(NMe2)3 and O2 plasma

Sharma

Longo

Verheijen

et al. 2016

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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HfO2 thin films were prepared by plasma-enhanced atomic layer deposition using a cyclopentadienyl-alkylamido precursor [HfCp(NMe2)3, HyALD™] and an O2 plasma over a temperature range of 150–400 °C at a growth per cycle around 1.1 Å/cycle. The high purity of the films was demonstrated by x-ray photoelectron spectroscopy and elastic recoil detection analyses which revealed that by increasing the deposition temperature from 200 to 400 °C, the atomic concentrations of residual carbon and hydrogen reduced from 1.0 to <0.5 at. % and 3.4 to 0.8 at. %, respectively. Moreover, Rutherford backscattering spectroscopy studies showed an improvement in stoichiometry of HfO2 thin films with the increase in deposition temperature, resulting in Hf/O ratio close to ∼0.5 at 400 °C. Furthermore, grazing incidence x-ray diffraction measurements detected a transition from amorphous at the deposition temperature of 300 °C to fully polycrystalline films at 400 °C, consisting of a mixture of monoclinic, tetragonal, and cubic phases. Finally, the surface morphology and conformality of HfO2 thin films studied by atomic force microscopy and transmission electron microscopy are also reported.

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Section: Resultsmentioning

confidence: 59%

Atomic layer deposition of HfO2 using HfCp(NMe2)3 and O2 plasma

Sharma

Longo

Verheijen

et al. 2016

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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show abstract

“…Cho et al 5152 clarified using density functional theory approach that, the interstitial defect is favoured under the oxygen-rich ambience whereas the substitutional form is more stable within the oxygen-deficient environment. More importantly, Choi et al 23 further pointed out that carbon atoms which induce trap levels inside the band gap can form a permanently conducting path once they percolate. This indicates that, similarly as V O which forms filaments contributing to a “soft” breakdown in RRAM devices, C residues can also form filaments which results in, however, “hard” breakdown.…”

Section: Resultsmentioning

confidence: 99%

Material insights of HfO2-based integrated 1-transistor-1-resistor resistive random access memory devices processed by batch atomic layer deposition

Niu

Kim

Roelofs

et al. 2016

Sci Rep

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With the continuous scaling of resistive random access memory (RRAM) devices, in-depth understanding of the physical mechanism and the material issues, particularly by directly studying integrated cells, become more and more important to further improve the device performances. In this work, HfO2-based integrated 1-transistor-1-resistor (1T1R) RRAM devices were processed in a standard 0.25 μm complementary-metal-oxide-semiconductor (CMOS) process line, using a batch atomic layer deposition (ALD) tool, which is particularly designed for mass production. We demonstrate a systematic study on TiN/Ti/HfO2/TiN/Si RRAM devices to correlate key material factors (nano-crystallites and carbon impurities) with the filament type resistive switching (RS) behaviours. The augmentation of the nano-crystallites density in the film increases the forming voltage of devices and its variation. Carbon residues in HfO2 films turn out to be an even more significant factor strongly impacting the RS behaviour. A relatively higher deposition temperature of 300 °C dramatically reduces the residual carbon concentration, thus leading to enhanced RS performances of devices, including lower power consumption, better endurance and higher reliability. Such thorough understanding on physical mechanism of RS and the correlation between material and device performances will facilitate the realization of high density and reliable embedded RRAM devices with low power consumption.

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“…Choi et al 35 using the first principles calculations showed that C Al can produce traps near/at the Al 2 O 3 /III-nitride interface. Based on these results as well as on the comparative electrical and photoelectric studies, Liu et al 36 suggested that the slow interface states at Al 2 O 3 /GaN interfaces originate from C impurities.…”

Section: A Properties Of D It (E)mentioning

confidence: 99%

“…According to some reports, [35][36][37] the origin of interface states at oxide/III-N interfaces can be related to C impurities near/at the interface. Choi et al 35 using the first principles calculations showed that C Al can produce traps near/at the Al 2 O 3 /III-nitride interface.…”

Section: A Properties Of D It (E)mentioning

confidence: 99%

On the origin of interface states at oxide/III-nitride heterojunction interfaces

Matys

Adamowicz

Domanowska

et al. 2016

Journal of Applied Physics

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The energy spectrum of interface state density, Dit(E), was determined at oxide/III-N heterojunction interfaces in the entire band gap, using two complementary photo-electric methods: (i) photo-assisted capacitance-voltage technique for the states distributed near the midgap and the conduction band (CB) and (ii) light intensity dependent photo-capacitance method for the states close to the valence band (VB). In addition, the Auger electron spectroscopy profiling was applied for the characterization of chemical composition of the interface region with the emphasis on carbon impurities, which can be responsible for the interface state creation. The studies were performed for the AlGaN/GaN metal-insulator-semiconductor heterostructures (MISH) with Al2O3 and SiO2 dielectric films and AlxGa1–x layers with x varying from 0.15 to 0.4 as well as for an Al2O3/InAlN/GaN MISH structure. For all structures, it was found that: (i) Dit(E) is an U-shaped continuum increasing from the midgap towards the CB and VB edges and (ii) interface states near the VB exhibit donor-like character. Furthermore, Dit(E) for SiO2/AlxGa1–x/GaN structures increased with rising x. It was also revealed that carbon impurities are not present in the oxide/III-N interface region, which indicates that probably the interface states are not related to carbon, as previously reported. Finally, it was proven that the obtained Dit(E) spectrum can be well fitted using a formula predicted by the disorder induced gap state model. This is an indication that the interface states at oxide/III-N interfaces can originate from the structural disorder of the interfacial region. Furthermore, at the oxide/barrier interface we revealed the presence of the positive fixed charge (QF) which is not related to Dit(E) and which almost compensates the negative polarization charge (Qpol−).

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Impact of carbon and nitrogen impurities in high-κ dielectrics on metal-oxide-semiconductor devices

Cited by 102 publications

References 29 publications

Atomic layer deposition of HfO2 using HfCp(NMe2)3 and O2 plasma

Atomic layer deposition of HfO2 using HfCp(NMe2)3 and O2 plasma

Material insights of HfO2-based integrated 1-transistor-1-resistor resistive random access memory devices processed by batch atomic layer deposition

On the origin of interface states at oxide/III-nitride heterojunction interfaces

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