GaAs and AlGaAs crystallographic etching with low-pressure chlorine radicals in an ultrahigh-vacuum system

Sugata, Sumio

doi:10.1116/1.583686

Cited by 34 publications

(6 citation statements)

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“…So, for deep trenches, the assumption of neutral shadowing seems reasonable. Perhaps Knudsen scattered neutrals do reach the bottom in the form of Cl 2 , but since Cl atoms are the more important etchant [42][43][44][45][46][47] the Knudsen diffusion of Cl 2 appears to have only a minor influence on the etching.…”

Section: A Aspect Ratio Scaling Mechanismsmentioning

confidence: 99%

“…The source and surface coverage of Cl is modeled by a single effective neutral etchant flux where the differences in reactivity and angular distribution between Cl, Cl 2 , Cl 2 ϩ , and Cl ϩ with Si 42,44 and GaAs 43,[45][46][47] are implicitly averaged. These assumptions are consistent with molecular and ion beam studies of both Si and GaAs etching.…”

Section: Ion-neutral Synergy Model With Langmuir Adsorption and Nomentioning

confidence: 99%

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Scaling of Si and GaAs trench etch rates with aspect ratio, feature width, and substrate temperature

Bailey

Sanden

Gregus

et al. 1995

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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The scaling of etch rates with feature dimensions is an important issue in the fabrication of microelectronic and photonic devices. Because etch rates depend on circuit layouts and design rules, considerable effort is spent to modify processes each time changes in design are made. Knowing how etch rates scale with design parameters should accelerate the introduction of new designs into manufacturing while minimizing the cost of doing so. Recently it has been shown that etch rates for a variety of conditions scale with the depth/width or aspect ratio and not on width or depth alone. While various mechanisms might be responsible for such scaling, isolating one mechanism from another is not straight forward. Nonetheless, it is important to understand the underlying mechanisms so that differences in etch chemistry and etch reactor design can be accounted for when scaling plasma processes from one design or reactor to another. To assess the effects of etch chemistry alone, the trench etch rates of Si and GaAs are compared under constant plasma conditions. Substrate temperature is varied to further assess the relative importance of surface vs transport phenomena during the etching process. At higher temperatures, both Si and GaAs trench etch rates scale only with aspect ratio in an Ar/Cl2 electron cyclotron resonance plasma. The results are consistent with an ion-neutral synergy model based on Langmuir adsorption kinetics where the scaling can be explained by the aspect ratio dependence of the neutral reactant transport into the trench: charging effects, ion shadowing, and Knudsen transport are not consistent with the data. At −45 °C, the etch rate no longer scales with aspect ratio alone, but now also depends on trench width. The data at this lower temperature are well described by a model incorporating the deposition of an etch inhibiting layer. While the trench etch rates for GaAs and Si scale in similar ways with aspect ratio and trench width, the dependence on feature dimensions of the Si etch rate is much stronger than that for GaAs at all substrate temperatures because the steady-state surface coverage of Cl is smaller for Si. This results in a greater sensitivity to the incoming, aspect ratio dependent, neutral fluxes. The implications of the models on the goal of aspect ratio independent etching are also discussed.

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Section: A Aspect Ratio Scaling Mechanismsmentioning

confidence: 99%

Section: Ion-neutral Synergy Model With Langmuir Adsorption and Nomentioning

confidence: 99%

Scaling of Si and GaAs trench etch rates with aspect ratio, feature width, and substrate temperature

Bailey

Sanden

Gregus

et al. 1995

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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“…Because of the technological importance of these processes, many studies (only some of which are listed here) have looked at how ion beams and plasmas (32)(33)(34)(35)(36)(37), as well as the individual constituents of plasmas [e.g. ions , atoms (38)(39)(40)(41), radicals (26,(42)(43)(44)(45), hot molecules (46,47), electrons (48)(49)(50)(51)(52)(53)(54)(55), and photons (56)(57)(58)(59)(60)(61)(62)(63)(64)(65)(66)(67)(68)(69)], act to etch semiconductor substrates.…”

Section: Introductionmentioning

confidence: 99%

Fundamental Studies of Halogen Reactions With Iii-v Semiconductor Surfaces

Simpson

Yarmoff

1996

Annu. Rev. Phys. Chem.

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It is technologically important to understand how halogens react with semiconductor surfaces because halogen compounds are commonly used to etch semiconductor wafers in the microelectronics industry. Halogens are also model adsorbates for studying chemisorption on covalently bonded materials, such as semiconductors, owing to the simple nature of the bonds that they form. The growing use of III-V materials in the manufacture of optoelectronic devices has prompted investigations of the reactions of molecular halogens (XeF 2 , Cl 2 , Br 2 , and I 2 ) with III-V semiconductor surfaces (GaAs, GaSb, InP, InAs, and InSb). This review examines the more fundamental of these investigations, which involve model systems in ultra-high vacuum, focusing on the chemistry of the halogen surface reactions and the physical and electronic structure of the reacted surfaces.

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“…11,[17][18][19][20] In the temperature range up to ϳ300°C only GaCl 3 , AsCl 3 and As reaction products were observed. 23 This ion assistance also drastically reduces the apparent activation energy for etching, leading to non-Arrhenius behavior. 11 McNevin published a Cl 2 /GaAs data base for ⌬H f 0 and S 0 values for all the potential etch products in this system and also found that GaCl 3 and AsCl 3 should be the main products ͑e.g., enthalpies for the mono-, di-, and trichlorides of Ga were Ϫ14.6, Ϫ54.5, and Ϫ99 kcal/mol, respectively, at 298 K͒.…”

Section: Introductionmentioning

confidence: 99%

Reactive ion beam etching of GaAs and related compounds in an inductively coupled plasma of Cl2–Ar mixture

Hahn¹,

Lee²,

Vawter³

et al. 1999

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Articles you may be interested inInductively coupled plasma-reactive ion etching of c-and a-plane AlGaN over the entire Al composition range: Effect of BCl3 pretreatment in Cl2/Ar plasma chemistry Reactive ion beam etching ͑RIBE͒ of GaAs, GaP, AlGaAs, and GaSb was performed in a Cl 2 -Ar mixture using an inductively coupled plasma source. The etch rates and yields were strongly affected by ion energy and substrate temperature. The RIBE was dominated by ion-assisted etching at Ͻ600 eV and by physical sputtering beyond 600 eV. The temperature dependence of the etch rates revealed three different regimes, depending on the substrate temperature: ͑1͒ sputtering-etch limited, ͑2͒ products-desorption limited, and ͑3͒ mass-transfer limited regions. GaSb showed the overall highest etch rates, while GaAs and AlGaAs were etched at the same rates. The etched features showed extremely smooth morphologies with anisotropic sidewalls.

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GaAs and AlGaAs crystallographic etching with low-pressure chlorine radicals in an ultrahigh-vacuum system

Cited by 34 publications

References 0 publications

Scaling of Si and GaAs trench etch rates with aspect ratio, feature width, and substrate temperature

Scaling of Si and GaAs trench etch rates with aspect ratio, feature width, and substrate temperature

Fundamental Studies of Halogen Reactions With Iii-v Semiconductor Surfaces

Reactive ion beam etching of GaAs and related compounds in an inductively coupled plasma of Cl2–Ar mixture

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