Physical and Electrical Properties of Al2O3, HfO2, and their Alloy Films Prepared by Atomic Layer Deposition for 65nm CMOS Gate Dielectric

Kawahara, T.; Torii, Kazuyoshi; Fukuda, S.; Maeda, Takeshi; Horiuchi, Atsushi; Ito, Hiroyuki; Muto, Akiyoshi; Kato, Yoshitake; Kitajima, Hiroshi

doi:10.1557/proc-745-n5.6

Cited by 4 publications

(4 citation statements)

References 5 publications

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“…The k values of HfAlO without nitrogen (in amorphous state 11,13,14) ) are also shown in this figure. It is demonstrated that the k values of HfAlON are higher than those of HfAlO over an entire composition range.…”

Section: Vg [V]mentioning

confidence: 92%

Cubic-HfN Formation in Hf-Based High-k Gate Dielectrics with N Incorporation and Its Impact on Electrical Properties of Films

Koyama¹,

Kamimuta²,

Koike³

et al. 2005

Jpn. J. Appl. Phys.

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We examined the effect of the annealing conditions on cubic-HfN (c-HfN) segregation in N-incorporated hafnium aluminate (HfAlON). Low-temperature activation (850 C, 30 min) leads to the inhibition of c-HfN segregation in HfAlON, which occurs at 1000 C for 30 s. This results in a reduced leakage current of the film in the 850 C annealing. k values of HfAlON (k $22) higher than those of hafnium aluminate are confirmed, through the polarization enhancement by Hf-N bonds without a long-range order of c-HfN. We also checked c-HfN segregation in N-incorporated HfO 2 (HfON) and N-incorporated hafnium silicate (HfSiON), by changing the annealing conditions. HfON causes the segregation of Hf 2 NO 2 and c-HfN at the 1065 C spike, whereas HfSiON maintains a homogeneous structure. We also found that, in the case of an excessive annealing of 1050 C for 30 min, HfSiON decomposes to HfO 2 /c-HfN. We think that the phase separation is thermodynamically favorable in N-incorporated Hf-based dielectrics at this temperature, however, HfSiON is fully sustainable under practical activation conditions for conventional complementary metal-oxide-semiconductor logic devices.

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Section: Vg [V]mentioning

confidence: 92%

Cubic-HfN Formation in Hf-Based High-k Gate Dielectrics with N Incorporation and Its Impact on Electrical Properties of Films

Koyama¹,

Kamimuta²,

Koike³

et al. 2005

Jpn. J. Appl. Phys.

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“…The HfLaO dielectrics were deposited on thermally grown SiO 2 layers by RF sputtering at room temperature. 11 The changes in the bulk properties of the HfLaO dielectrics depending on the La concentration (Hf:La = 10:0, 7:3, 5:5, 3:7) were examined using 20-nm-thick oxide films deposited on thick thermal SiO 2 underlayers (600 nm). Considering the practical application of the scaled high-k dielectrics, stacked structures composed of 1-nm-thick HfLaO films (Hf:La = 7:3, 3:7) deposited on 1-nm-thick SiO 2 underlayers were also prepared, and they were then annealed in N 2 ambient at 600 C in order to study the effect of the thermal treatment on the ultrathin oxides.…”

Section: Methodsmentioning

confidence: 99%

Electronic Structure Characterization of La Incorporated Hf-Based High-k Gate Dielectrics by NEXAFS

Yamamoto¹,

Ogawa²,

Kunisu³

et al. 2011

J. Nanosci. Nanotech.

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The electronic structures of lanthunum (La) incorporated hafnium (Hf)-based oxides (HfLaO) and their silicate (HfLaSiO) films were investigated by the Near Edge X-ray Absorption Fine Structure (NEXAFS) technique. The oxygen (O) K-edge spectra, which reflected the hybridized Hf 5d state with the O 2p orbital, were found to reveal features of the unoccupied state of the metal oxides, as well as the conduction-band edge. We also found that, while La incorporation into the Hf-based oxides simply changed the features of the conduction-band structure, subsequent thermal annealing of the La-incorporated films led to a conduction-band edge shift due to an interface silicate reaction and/or local bond rearrangement depending on the La concentration and annealing temperature. The impact of La incorporation into the Hf-based high-k materials on the electronic structure is discussed by taking into account the intrinsic nature of these metal oxides.

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“…The samples used in the present experiments were 7-nm-thick Hf 0.3 Al 0.7 O x films deposited on Si substrates using an atomic layer deposition (ALD) [17]. Before the deposition, 0.9-nm-thick SiON films were grown by wet oxidation using N 2 O/H 2 .…”

Section: Methodsmentioning

confidence: 99%

Study of high‐k gate dielectrics by means of positron annihilation

Uedono

Naito

Otsuka

et al. 2007

Phys. Status Solidi (c)

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PACS 77.55.+f, 78.70.Bj High-dielectric constant (high-k) gate materials, such as HfSiO x and HfAlO x , fabricated by atomic-layerdeposition techniques were characterized using monoenergetic positron beams. Measurements of the Doppler broadening spectra of annihilation radiation and the lifetime spectra of positrons indicated that positrons annihilated from the trapped state by open volumes that exist intrinsically in amorphous structures of the films. The size distributions of the open volumes and the local atomic configurations around such volumes can be discussed using positron annihilation parameters, and they were found to correlate with the electrical properties of the films. We confirmed that the positron annihilation is useful technique to characterize the matrix structure of amorphous high-k materials, and can be used to determine process parameters for the fabrication of high-k gate dielectrics. 1 Introduction According to the international technology roadmap for semiconductors [1], the technology node for mass production of LSI devices will reach the 45-nm level in 2010; as a result, the need to replace SiO 2 with high-dielectric (high-k) materials will be indispensable for fabrication of metal-oxidesemiconductor field effect transistors (MOSFETs). Among many candidates for high-k materials, hafnium (Hf) based oxides (such as HfAlO x and HfSiO x ) have advantages such as a moderately high dielectric constant and high thermal stability in contact with Si [2,3]. Although the electric properties of MOS using metal oxides have been intensively studied, behaviour of the metal oxides during device processing is not fully understood. This might be due to a lack of techniques to characterize very thin films (≤5 nm). Positron annihilation is one established technique for investigating defects in materials [4]. Point defects in transition-metal oxides have been investigated by using positron annihilation [5][6][7][8][9][10][11][12], and the results show that positrons are a useful probe for studying vacancy-type defects in such materials. Thin high-k dielectrics deposited on Si substrates were characterized also using monoenergetic positron beams [13][14][15][16]. In the present study, we used this technique to probe open volumes in thin HfAlO x and HfSiO x films.

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Physical and Electrical Properties of Al₂O₃, HfO₂, and their Alloy Films Prepared by Atomic Layer Deposition for 65nm CMOS Gate Dielectric

Cited by 4 publications

References 5 publications

Cubic-HfN Formation in Hf-Based High-k Gate Dielectrics with N Incorporation and Its Impact on Electrical Properties of Films

Cubic-HfN Formation in Hf-Based High-k Gate Dielectrics with N Incorporation and Its Impact on Electrical Properties of Films

Electronic Structure Characterization of La Incorporated Hf-Based High-<I>k</I> Gate Dielectrics by NEXAFS

Study of high‐k gate dielectrics by means of positron annihilation

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