Polysilicon gate etching in high density plasmas. V. Comparison between quantitative chemical analysis of photoresist and oxide masked polysilicon gates etched in HBr/Cl2/O2 plasmas

Bell, F. H.; Joubert, O.

doi:10.1116/1.589259

Cited by 54 publications

(9 citation statements)

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“…Lau and coworkers [9][10][11][12][13][14][15] have published several articles, dealing with various structural and electrical properties of ultrathin dielectric films on semiconductors using surface charging. Thomas et al [16] were able to separate various electrically uncoupled regions on an integrating circuit surface using the surface charging effect; and similar applications were also reported by Ermolieff et al [17] and Bell and Joubert [18]; while Miller et al applied the technique to separate the XPS signals of the fiber from the exposed matrix at fractured surfaces [19]. Use of surface charging for lateral differentiation of mesoscopic layers and for depth profiling in 1-10 nm thin layers have also recently been reported [20,21].…”

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confidence: 71%

XPS analysis with pulsed voltage stimuli

2006

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We record XPS spectra while applying 0 to +10 V or 0 to À10 V square pulses to the sample rod, which normally results in twinning of all peaks at correspondingly increased (for +10 V) or decreased (for À10 V) binding energies. For poorly conducting samples, like silicon oxide layer on a silicon substrate, the twinned peaks appear at different energies due to differential charging, which also vary with respect to the frequency of the applied pulses. Moreover, the frequency dependence varies with the thickness and can be correlated with the capacitance of the oxide layer. The technique is simple and can lead to extract important information related with dielectric properties of surface structures in a totally non-contact fashion. Ó 2005 Elsevier B.V. All rights reserved.Keywords: X-ray photoelectron spectroscopy; Differential charging; Silicon dioxide layers; Capacitance X-ray photoelectron spectra are normally recorded while the samples are electrically tied to the spectrometer ground to avoid disturbances due to contact potentials and/or charging. Even then, positive charging (commonly referred as surface charging or differential charging) is unavoidable in analysis of poorly conducting samples as a result of incomplete neutralization [1][2][3][4][5][6]. Use of a lowenergy electron flood gun, for neutralization, has been very successful for most applications [7,8]. Over-neutralization (using the flood gun) leading to excess negative charging is also encountered.Utilization of surface charging (mostly negative) phenomenon, for elucidating chemical and/or structural parameters of various materials, has also been reported. Lau and coworkers [9][10][11][12][13][14][15] have published several articles, dealing with various structural and electrical properties of ultrathin dielectric films on semiconductors using surface charging. Thomas et al. [16] were able to separate various electrically uncoupled regions on an integrating circuit surface using the surface charging effect; and similar applications were also reported by Ermolieff et al. [17] and Bell and Joubert [18]; while Miller et al. applied the technique to separate the XPS signals of the fiber from the exposed matrix at fractured surfaces [19]. Use of surface charging for lateral differentiation of mesoscopic layers and for depth profiling in 1-10 nm thin layers have also recently been reported [20,21]. By adopting a different strategy, we have also reported that by application of a small (1-10 V) bias we can control the differential charging to obtain a variety of analytical information about surface structures [23][24][25].The technique of biasing the sample goes back (three decades) to the early days of XPS [1,2]. However, use of it for extracting chemical and/or structural information is not extensive. In a recent application Havercroft and Sherwood [22] showed that biasing the sample holder, with a large negative d.c. voltage (25-100 V), could be used to identify chemical differences in oxide films on an aluminum alloy. In our previous reports ...

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confidence: 71%

XPS analysis with pulsed voltage stimuli

2006

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“…To characterize the surface layer on reactor walls, other researchers have looked at surfaces in situ by total internal reflection Fourier transform IR (TIR-FTIR) spectroscopy, , and laser-induced thermal desorption, − or after plasma exposure by vacuum-sample-transfer X-ray photoelectron spectroscopy (XPS). − While yielding information on the buildup and removal of surface species, these methods do not provide recombination coefficients, sticking coefficients, or surface kinetics. The TIR-FTIR method is also limited to IR-transparent surfaces such as GaAs, as opposed to the more common reactor materials, anodized aluminum and SiO 2 .…”

Section: Introductionmentioning

confidence: 99%

Recombination Reactions of Oxygen Atoms on an Anodized Aluminum Plasma Reactor Wall, Studied by a Spinning Wall Method

2005

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We have studied the recombination of O atoms on an anodized Al surface in an oxygen plasma, using a new "spinning wall" technique. With this method, a cylindrical section of the wall of the plasma reactor is rotated and the surface is periodically exposed to an oxygen plasma and then to a differentially pumped mass spectrometer (MS). By varying the substrate rotation frequency (r), we vary the reaction time (t(r)), that is, the time between exposure of the surface to O atoms in the plasma and MS detection of desorbing O(2) (t(r) = 1/2r). As t(r) is increased from 0.7 to 40 ms, the O(2) desorption signal decreases by a factor of 2 for an O-atom flux of 1 x 10(16) cm(-2) s(-1) and by a factor of 6 when the O flux is 1 x 10(17) cm(-2) s(-1). The O(2) signal decay is highly nonexponential, slowing at longer times and reaching zero signal as r --> 0. A model of O-atom recombination is compared with these time-dependent results. The model assumes adsorption occurs at surface sites with a range of binding energies. O can detach from these sites, become mobile, and diffuse along the surface. This leads to desorption of O, reattachment at free adsorption sites, and recombination to form O(2) that promptly desorbs. With several adjustable parameters, the model reproduces the observed shapes of the O(2) desorption decay curves and the lack of detectable desorption of O and predicts a high O-atom recombination coefficient on anodized aluminum.

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“…To meet these requirements, a deeper understanding of plasma-surface interactions underlying the processing is increasingly important on the atomic scale. A number of experiments have been concerned with Si etching in Cl 2 -, Br 2 -, and HBr-containing plasmas to reveal the surface reaction kinetics during etching such as ionenhanced etching and passivation layer formation through investigating the etch yield and threshold, 9,10 and the microscopic surface structures of reaction [11][12][13][14] and passivation [15][16][17][18] layers, e.g., their thickness, coverage, and depth profile of halogen and other atoms adsorbed, and stoichiometry and depth profile of reaction products contained therein. However, the surface reaction kinetics during plasma etching are not yet fully understood owing to the plasma environments of enormous complexity.…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics simulations of Si etching in Cl- and Br-based plasmas: Cl+ and Br+ ion incidence in the presence of Cl and Br neutrals

Nakazaki

Takao

Eriguchi

et al. 2015

Journal of Applied Physics

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Classical molecular dynamics (MD) simulations have been performed for Cl+ and Br+ ions incident on Si(100) surfaces with Cl and Br neutrals, respectively, to gain a better understanding of the ion-enhanced surface reaction kinetics during Si etching in Cl- and Br-based plasmas. The ions were incident normally on surfaces with translational energies in the range Ei = 20–500 eV, and low-energy neutrals of En = 0.01 eV were also incident normally thereon with the neutral-to-ion flux ratio in the range Γn0/Γi0 = 0–100, where an improved Stillinger--Weber potential form was employed for the interatomic potential concerned. The etch yields and thresholds presently simulated were in agreement with the experimental results previously reported for Si etching in Cl2 and Br2 plasmas as well as in Cl+, Cl2+, and Br+ beams, and the product stoichiometry simulated was consistent with that observed during Ar+ beam incidence on Si in Cl2. Moreover, the surface coverage of halogen atoms, halogenated layer thickness, surface stoichiometry, and depth profile of surface products simulated for Γn0/Γi0 = 100 were in excellent agreement with the observations depending on Ei reported for Si etching in Cl2 plasmas. The MD also indicated that the yield, coverage, and surface layer thickness are smaller in Si/Br than in Si/Cl system, while the percentage of higher halogenated species in product and surface stoichiometries is larger in Si/Br. The MD further indicated that in both systems, the translational energy distributions of products and halogen adsorbates desorbed from surfaces are approximated by two Maxwellians of temperature T1 ≈ 2500 K and T2 ≈ 7000–40 000 K. These energy distributions are discussed in terms of the desorption or evaporation from hot spots formed through chemically enhanced physical sputtering and physically enhanced chemical sputtering, which have so far been speculated to both occur in the ion-enhanced surface reaction kinetics of plasma etching.

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Polysilicon gate etching in high density plasmas. V. Comparison between quantitative chemical analysis of photoresist and oxide masked polysilicon gates etched in HBr/Cl2/O2 plasmas

Abstract: Articles you may be interested inTungsten metal gate etching in Cl 2 ∕ O 2 inductively coupled high density plasmas

Cited by 54 publications

References 4 publications

XPS analysis with pulsed voltage stimuli

XPS analysis with pulsed voltage stimuli

Recombination Reactions of Oxygen Atoms on an Anodized Aluminum Plasma Reactor Wall, Studied by a Spinning Wall Method

Molecular dynamics simulations of Si etching in Cl- and Br-based plasmas: Cl+ and Br+ ion incidence in the presence of Cl and Br neutrals

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