Sidewall roughness during dry etching of InP

Chakrabarti, U. K.; Pearton, S. J.; Ren, F.

doi:10.1088/0268-1242/6/5/018

Cited by 29 publications

(14 citation statements)

References 6 publications

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“…1-12 Due to the low volatility of indium chlorides, it is necessary to increase substrate temperatures ͑i.e., to above about 200°C͒ to prevent severe surface roughening. [27][28][29][30][31][32][33][34][35][36] Most plasma etching reported was carried out in either capacitively coupled plasmas ͑CCP͒ or electron cyclotron resonance plasma ͑ECR͒ reactors. Although chlorofluorocarbons do not suffer from this problem, their usage is strictly controlled by environmental legislation, as they can cause depletion of the ozone layer.…”

Section: Introductionmentioning

confidence: 99%

Inductively coupled plasma etching of InP using CH4/H2 and CH4/H2/N2

Chen

Ruda

2002

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

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Inductively coupled plasma etching of InP in CH 4 /H 2 and CH 4 /H 2 /N 2 gas mixtures was studied to understand the etching mechanisms and the influence of etching gas composition on etching rate, etching profile, and surface morphology. CH 4 /H 2 plasmas generally had higher etching rates than CH 4 /H 2 /N 2 plasmas. Deterioration of InP surfaces, following etching, reflected the preferential loss of P over In due to the diffusivity and reactivity of H being higher than CH 3 on InP surfaces, and also since PH 3 is more volatile than In(CH 3 ) 3 . In extreme circumstances, this can lead to the formation of In-rich droplets on the surface, with associated surface roughening. This was supported by the opposing trends of surface roughness ͑measured using atomic force microscopy͒ and P/In ratio ͑from x-ray photoelectron spectroscopy͒ as a function of the CH 4 gas concentration for CH 4 /H 2 gas mixtures. The addition of N 2 to the CH 4 /H 2 plasmas improved the surface morphology as N radicals reduced the rate of P removal by reacting with H radicals. However, an inevitable increase in the N ϩ and N 2 ϩ concentrations led to erosion of the SiO 2 masks and caused sloping sidewalls.

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Section: Introductionmentioning

confidence: 99%

Inductively coupled plasma etching of InP using CH4/H2 and CH4/H2/N2

Chen

Ruda

2002

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

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“…This effect is shown in the SEM micrographs of Fig. 17 Figure 5 ͑top͒ shows SEM micrographs of a 1.5-m-thick InGaP layer on a GaAs substrate after a short etch in BCl 3 N 2 at 1000 W that ends ϳ1.5 m into the GaAs. Note also that the vertical striations on the sidewalls are present on both InGaP and GaAs, and originate from roughness on the edge of the photoresist that was used to mask the SiN X during its patterning.…”

Section: Resultsmentioning

confidence: 91%

BCl3/N2 dry etching of InP, InAlP, and InGaP

Ren

Lothian

Kuo

et al. 1996

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

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Reduction of gap states of ternary III-V semiconductor surfaces by sulfur passivation: Comparative studies of AlGaAs and InGaPEtch rates for InP, InAlP, and InGaP can be controlled between ϳ1500 Å/min and Ͼ1 m/min by varying the microwave power, rf power, or N 2 composition in BCl 3 N 2 discharges under electron cyclotron resonance conditions. The surface morphology of InGaP is poor at low microwave power ͑250 W͒, but becomes very smooth at high powers ͑1000 W͒. InP has exactly the opposite dependence on microwave power, while InAlP shows little change in morphology over a wide range of powers. The high ion current under electron cyclotron resonance conditions enables etching of In-based semiconductors without the need for high sample temperatures to enhance desorption of InCl X species.

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“…The etching is smooth and straight, with the corrugated features on the sidewall having been transferred into the semiconductor from the initial roughness in the edges of the resist mask, as reported previously. 36 Figure 7 ͑top͒ shows a feature etched with 2.5 sccm N 2 flow in which the onset of polymer sheet formation is obvious. When the rf bias was reduced to 50 from 75 W, and the microwave power lowered from 850 to 500 W we still observed anisotropic etching ͓Fig.…”

Section: Resultsmentioning

confidence: 99%

Etching of GaAs/AlGaAs rib waveguide structures using BCl3/Cl2/N2/Ar electron cyclotron resonance

Constantine

1995

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

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An anisotropic nonselective etch for GaAs/AlGaAs rib waveguides has been developed for use under electron cyclotron resonance conditions. The plasma chemistry features BCl3 to minimize AlGaAs oxidation effects and small additions of N2 to induce sidewall protection when using photoresist masks. The fundamental mode attenuation in GaAs/AlGaAs waveguides is sensitive to the choice of both plasma chemistry and masking material, but can be reduced to ≤1 dB cm−1 for channel widths of 4–5 μm.

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Sidewall roughness during dry etching of InP

Cited by 29 publications

References 6 publications

Inductively coupled plasma etching of InP using CH4/H2 and CH4/H2/N2

Inductively coupled plasma etching of InP using CH4/H2 and CH4/H2/N2

BCl3/N2 dry etching of InP, InAlP, and InGaP

Etching of GaAs/AlGaAs rib waveguide structures using BCl3/Cl2/N2/Ar electron cyclotron resonance

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