Optical and Electrical Characterization of Hydrogen-Plasma-Damaged Silicon Surface Structures and Its Impact on In-line Monitoring

Nakakubo, Yoshinori; Matsuda, Asahiko; Fukasawa, Masanaga; Takao, Yoshinori; Tatsumi, Tetsuya; Eriguchi, Koji; Ono, Ken

doi:10.1143/jjap.49.08jd02

Cited by 55 publications

(64 citation statements)

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“…The thicknesses of both the oxidized and dislocated Si layers are quite consistent with previously reported results measured by spectroscopic ellipsometry. 15 The depth of H-induced damage is more than 20 nm, which is much deeper than those of the Ar-and O-induced damages. The depth profile of the damaged layer is strongly related to the penetration depth of incident ions.…”

Section: Resultsmentioning

confidence: 93%

“…The Si substrate damage was analyzed by spectroscopic ellipsometry (SE), HRBS, and TEM. In the SE analysis, data were fitted using a three-layer model (SiO 2 /dislocated Si/ substrate) 15 wherein dislocated Si was modeled as a mixture of SiO 2 and polysilicon by using the Bruggeman effective medium approximation. 16,17 Current-voltage (C-V) charac-teristics were measured with a mercury probe system without introducing any additional damage by forming electrodes.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Structural and electrical characterization of HBr/O2 plasma damage to Si substrate

Fukasawa¹,

Nakakubo

Matsuda

et al. 2011

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

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Silicon substrate damage caused by HBr/O 2 plasma exposure was investigated by spectroscopic ellipsometry (SE), high-resolution Rutherford backscattering spectroscopy, and transmission electron microscopy. The damage caused by H 2 , Ar, and O 2 plasma exposure was also compared to clarify the ion-species dependence. Although the damage basically consists of a surface oxidized layer and underlying dislocated Si, the damage structure strongly depends on the incident ion species, ion energy, and oxidation during air and plasma exposure. In the case of HBr/O 2 plasma exposure, hydrogen generated the deep damaged layer ($10 nm), whereas ion-enhanced diffusion of oxygen, supplied simultaneously by the plasma, caused the thick surface oxidation. In-line monitoring of damage thicknesses by SE, developed with an optimized optical model, showed that the SE can be used to precisely monitor damage thicknesses in mass production. Capacitance-voltage (C-V) characteristics of a damaged layer were studied before and after diluted-HF (DHF) treatment. Results showed that a positive charge is generated at the surface oxide-dislocated Si interface and/or in the bulk oxide after plasma exposure. After DHF treatment, most of the positive charges were removed, while the thickness of the "Si recess" was increased by removing the thick surface oxidized layer. As both the Si recess and remaining dislocated Si, including positive charges, cause the degradation of electrical performance, precise monitoring of the surface structure and understanding its effect on device performance is indispensable for creating advanced devices. V

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Section: Resultsmentioning

confidence: 93%

Section: Methodsmentioning

confidence: 99%

Structural and electrical characterization of HBr/O2 plasma damage to Si substrate

Fukasawa¹,

Nakakubo

Matsuda

et al. 2011

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

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“…The SE technique is widely used for studying structural and material properties [23][24][25] and as in-line monitoring for PPD measurement. 22,[25][26][27] In the present experiments, the SE spectra were obtained in the photon energy range from 1.5 to 5.5 eV. We determined the optical thickness of SL and IL.…”

Section: B Damage Evaluation Techniquesmentioning

confidence: 99%

Influence of microwave annealing on optical and electrical properties of plasma-induced defect structures in Si substrate

Iwai

Eriguchi

Yamauchi

et al. 2015

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

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The authors investigate the effects of microwave annealing (MWA) on the recovery of plasma process-induced ion-bombardment damage in Si substrates. For damage creation, Ar discharges by a capacitively coupled plasma etcher are used. For damage repairing, the MWA or a rapid thermal annealing (RTA) are conducted. The authors employ spectroscopic ellipsometry (SE), photoreflectance spectroscopy (PRS), and capacitance-voltage () measurement to analyze the damaged structures. Recovery of the damage is discussed by comparing the obtained parameters before and after the annealing processes. In the SE analysis, the change in the real part of dielectric constant (Δ) is investigated. The Δ spectral peak around 3.4 eV decreases with an increase in the annealing temperature () for both MWA and RTA, indicating the decrease in the density of defects created in the Si substrate. In the PRS analysis, the spectral peak intensity is found to decrease by the plasma exposure, and then to increase with , which implies the recovery of the Si crystalline structure by MWA as well as by RTA. In the measurement, the voltage shift (Δ) in the respective curves is used as a measure of the number of defects present in the surface and interface damaged regions. The Δ in the negative bias direction is observed after the plasma exposure for all damaged structures, while after annealing the Δ in the positive bias direction is confirmed, suggesting the recovery of the damage in the surface and interface regions. Moreover, it is experimentally found that MWA induces larger |Δ| than RTA. These findings indicate the decrease in carrier trap sites in the surface and interface regions of damaged structures, and that MWA is more effective in repairing such damage than RTA. The authors propose a model explaining these mechanisms where defect-induced dipole moments that interact with the incident microwave are considered. The present results draw a new damage-recovery picture by MWA, in particular, for plasma-induced damage in surface and interface regions of Si substrates.

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“…This means that backward flow of NF 3 does not take place (owing to viscous flow). This etch rate dependence on the N 2 flow rate ratio is very useful to remove the damaged Si layer of approximately 10 nm around gate electrode [16][17][18], where clean removing the damaged layer without any etched residues is required, and is also to be controllable within 1 to 2 minutes by changing the N 2 flow rate ratio. Figure 3 shows a schematic diagram of the reaction chamber, in which NF 3 is fed 20-40 cm from the edge of the discharge area at pressures of 100-500 Pa [26].…”

Section: Cde Technologies With Long Life Time Plasma Sourcementioning

confidence: 99%

“…However, this technology turns into a very important one because the removal of damaged Si layer around the gate electrode and residual oxide layer after gate oxide are strongly required in the ultrafine pattern fabrication with a half pitch lower than 45 nm. In these process, slow etch rate is required in order to control the etched depth of around 10 nm, which is damaged by a prior reactive ion etching [16][17][18], or remains in a prior oxide etching.…”

Section: Introductionmentioning

confidence: 99%

Recent Development of Si Chemical Dry Etching Technologies

Hayashi¹

2013

J Nanomed Nanotechnol

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Chemical dry etching in wafer processing was innovated and developed in 1976 using CF 4 /O 2 downflow plasma for poly-Si etching. Thereafter, many researchers developed and reported various chemical dry etching methods. Advanced Si chemical dry etching technology was developed in 2010, using N 2 downflow plasma and NF 3 flowing to the downflow plasma area. The etchant production mechanism for this technology was explained by us. In these technologies, the plasma source is necessary to produce the etchants (F for Si etching and HF+NH 3 for SiO 2 etching). Recently, a novel Si chemical dry etching technology was innovated and developed by us without plasma source, in which F atoms generated in F 2 +NOF+FNO reaction are used for Si etching in the pressure range of 100 to 1000 Pa. The etch rate at room temperature is more than 5000 nm/min, and is dependent on the flow rate and on the distance between the gas mixing point and the wafer position. Increasing the substrate temperature, the minimum etch rate was obtained at 60 º C. Over this temperature, the etch rate increased again with increase of the substrate temperature. In the lower temperature region, the chemisorbed layer may be formed and the chemical reaction may be enhanced in this condensed layer. Increasing the temperature, this chemisorbed layer disappears around 60 º C. Over this temperature, the surface reaction mainly takes place according to Arrhenius equation. Journal of Nanomedicine & Nanotechnology J o u rna l of N a n o m ed icine & N a n o te chnolo g y

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Optical and Electrical Characterization of Hydrogen-Plasma-Damaged Silicon Surface Structures and Its Impact on In-line Monitoring

Cited by 55 publications

References 50 publications

Structural and electrical characterization of HBr/O2 plasma damage to Si substrate

Structural and electrical characterization of HBr/O2 plasma damage to Si substrate

Influence of microwave annealing on optical and electrical properties of plasma-induced defect structures in Si substrate

Recent Development of Si Chemical Dry Etching Technologies

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