Effective work function modulation of TaN metal gate on HfO2 after postmetallization annealing

Sugimoto, Yuichi; Kajiwara, Masanari; Yamamoto, Keisuke; Suehiro, Yuta; Wang, Dong; Nakashima, Hiroshi

doi:10.1063/1.2783472

Cited by 32 publications

(12 citation statements)

References 14 publications

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“…Note that this wet etching method enables us to perform selective etching of TiN film on SiO 2 and high-k dielectrics such as HfO 2 and HfSiON. 7 Finally, contact annealing was carried out at 350°C for 10 min in N 2 for obtaining electrically good adhesion between Al and TiN films.…”

Section: Postmetallization Annealing Effect Of Tin-gate Ge Metal-oxidmentioning

confidence: 99%

Postmetallization annealing effect of TiN-gate Ge metal-oxide-semiconductor capacitor with ultrathin SiO2/GeO2 bilayer passivation

Nakashima

Iwamura

Sakamoto

et al. 2011

Applied Physics Letters

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The postmetallization annealing (PMA) effect was investigated for a TiN-gate Ge metal-oxide-semiconductor capacitor with an ultrathin SiO2/GeO2 bilayer passivation. PMA at 450 °C led to the incorporation of nitrogen atoms into the gate stack. Consequently, the flat band voltage shifted from −0.79 to +0.23 V, resulting from a decrease in the dipole at the SiO2/GeO2 interface and the accompanying creation of a negative charge. The hysteresis decreased from 98 to 27 mV and the interface state density decreased from 6×1011 to 2.5×1011 cm−2 eV−1, as results of the nitrogen termination of defects at the SiO2/GeO2 interface and/or in the GeO2 interlayer.

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Section: Postmetallization Annealing Effect Of Tin-gate Ge Metal-oxidmentioning

confidence: 99%

Postmetallization annealing effect of TiN-gate Ge metal-oxide-semiconductor capacitor with ultrathin SiO2/GeO2 bilayer passivation

Nakashima

Iwamura

Sakamoto

et al. 2011

Applied Physics Letters

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“…[15][16][17][18][19] In the current case, the interfacial metal oxides formed during the sputter deposition of HfO 2 are likely due to the high-energy, gas-phase oxygen ions formed when the HfO 2 target is bombarded with high-energy argon ions. Such oxygen ions are highly reactive and are even capable of oxidizing noble metals such as platinum and forming high-oxidation-state oxides for the other metals (W, Cr, Cu, and Al).…”

Section: Introductionmentioning

confidence: 99%

Effects of interfacial oxide layers of the electrode metals on the electrical characteristics of organic thin-film transistors with HfO2 gate dielectric

Tang

Greiner

Helander

et al. 2011

Journal of Applied Physics

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Articles you may be interested inAtomic layer deposition grown metal-insulator-metal capacitors with RuO 2 electrodes and Al-doped rutile TiO 2 dielectric layer J. Vac. Sci. Technol. B 29, 01AC09 (2011); 10.1116/1.3534023 Electrode effects on the conduction mechanisms in HfO 2 -based metal-insulator-metal capacitors Characteristics of metal-insulator-semiconductor capacitors based on high-k HfAlO dielectric films obtained by low-temperature electron-beam gun evaporation Appl. Phys. Lett. 85, 5950 (2004); 10.1063/1.1836875Metal-insulator-metal capacitors using Y 2 O 3 dielectric grown by pulsed-injection plasma enhanced metalorganic chemical vapor deposition HfO 2 -based devices employing various electrode metals (Al, W, Pt, Cu, and Cr) were fabricated and characterized in order to examine the importance of the choice of metal electrode when sputter-depositing HfO 2 films. It was found that metal-insulator-metal capacitors with an Al bottom electrode exhibit a significantly smaller leakage current and a larger breakdown field strength than devices using W, Pt, Cu, and Cr electrodes. By examining HfO 2 /metal interfaces with x-ray photoelectron spectroscopy, it was found that metal electrodes are oxidized during the deposition of HfO 2 , resulting in interfacial oxide layers of the electrode metals (Al 2 O 3 , WO 3 , PtO, CuO, and Cr 2 O 3 þ CrO 3 ) between the metal electrode and the HfO 2 layer. The formation of a metal oxide interlayer is a consequence of the high-energy oxygen ions generated during HfO 2 sputtering. The difference in the device performance was attributed to the electronic properties of the oxide interlayers. It was found that when the oxide interlayers are semiconducting (e.g., WO 3 , PtO, CuO, or Cr 2 O 3 þ CrO 3 ), devices have high leakage currents and low breakdown field strengths, and an insulating oxide interlayer (Al 2 O 3 ) enhances these device characteristics. Organic thin-film transistors (OTFTs) using a HfO 2 dielectric layer showed that an Al gate has a much lower offstate current, larger on/off ratio, and smaller sub-threshold slope compared with OTFTs using a Cr electrode. These results demonstrate the importance of the metal gate electrode and the electrical characteristics of its oxide when using the sputter-deposition of HfO 2 to fabricate thin-film transistors.

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“…The binding energies (BE) at around 19.7 and 18.1 eV in Fig. 4(a) correspond to Hf 415/2 and Hf 4f7/2, respectively, which come from the HfD2/HfxSil_xOy bilayer film [7]. The results of Fig.…”

Section: Methodsmentioning

confidence: 96%

“…Here, the PDA condition was F o2 =5 sccm (corresponding to 6xl0-1 Pa) at 550°C for 10 min. Before XPS measurements, the TaN film on the sample was removed by wet etching using NH 4 0HlH 2 0 2 solution at room temperature [7]. Figures 4(a) and 4(b) show the XPS spectra obtained from Hf 4/ and Si 2p core levels at a photo electron take-off angle of 90°, where Hf 4/and Si 2p spectra were calibrated using a Hf 5p3/2 core level (33.8 eV) and a bulk Si 2p core level (99.3 eV), respectively.…”

Section: Ieot=12nm Imentioning

confidence: 99%

Fabrication of high-k gate dielectrics using plasma oxidation and subsequent annealing of Hf/SiO<inf>2</inf>/Si structure

Nakashima

Sugimoto

Suehiro

et al. 2008

2008 9th International Conference on Solid-State and Integrated-Circuit Technology

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High-permittivity (high-k) dielectrics with HtD 2 IHf x Si 1 _ x OylSi structures were fabricated using plasma oxidation and subsequent annealing of HflSi0 2 /Si structure. By replacing Si0 2 film of initial structure from plasma oxidized Si0 2 to thermal oxidized Si0 2 , the drastic decrease of traps in interfacial layer (IL: HfxSi1_xO y ) could be successfully achieved, which shows interface state density of 1xlOll ey·lcm-2 , effective oxide thickness (EOT) of 1.2 nm, and 4 orders decrease of leakage current density relative to Si0 2 with EOT of 1.2 nm. The influence of post annealing on structural and electrical properties of IL was investigated by using XPS analysis and TEM observation. It was clarified that the increase of EOT after post annealing at 900°C is caused by the decrease of Hf content in IL and the increase of IL thickness. The kinetics of IL formation is discussed in details.

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Effective work function modulation of TaN metal gate on HfO2 after postmetallization annealing

Cited by 32 publications

References 14 publications

Postmetallization annealing effect of TiN-gate Ge metal-oxide-semiconductor capacitor with ultrathin SiO2/GeO2 bilayer passivation

Postmetallization annealing effect of TiN-gate Ge metal-oxide-semiconductor capacitor with ultrathin SiO2/GeO2 bilayer passivation

Effects of interfacial oxide layers of the electrode metals on the electrical characteristics of organic thin-film transistors with HfO2 gate dielectric

Fabrication of high-k gate dielectrics using plasma oxidation and subsequent annealing of Hf/SiO<inf>2</inf>/Si structure

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