The selectivity of poly Si and SiO2 etching using a negative dc biasing of powered electrode

Brčka, Jozef; Harman, R.; Blackburn, A. C.

doi:10.1016/0042-207x(86)90241-1

Cited by 2 publications

(1 citation statement)

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“…However, owing to the limitations of our equipment, only the source and bias powers and the components of the etching gas mixture were investigated. The source and bias powers were studied to control the energy of the ions bombarding the wafer during anisotropic profile creation and etch rate enhancement [28,[30][31][32][33][34][35]. The etching gas ratios of NF 3 and O 2 were studied to clarify the surface reactions that occurred during etching.…”

Section: Resultsmentioning

confidence: 99%

Enhancing Si3N4 Selectivity over SiO2 in Low-RF Power NF3–O2 Reactive Ion Etching: The Effect of NO Surface Reaction

Tung,

Lee,

Dinh

et al. 2024

Sensors

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Highly selective etching of silicon nitride (Si3N4) and silicon dioxide (SiO2) has received considerable attention from the semiconductor community owing to its precise patterning and cost efficiency. We investigated the etching selectivity of Si3N4 and SiO2 in an NF3/O2 radio-frequency glow discharge. The etch rate linearly depended on the source and bias powers, whereas the etch selectivity was affected by the power and ratio of the gas mixture. We found that the selectivity can be controlled by lowering the power with a suitable gas ratio, which affects the surface reaction during the etching process. X-ray photoelectron spectroscopy of the Si3N4 and QMS measurements support the effect of surface reaction on the selectivity change by surface oxidation and nitrogen reduction with the increasing flow of O2. We suggest that the creation of SiOxNy bonds on the surface by NO oxidation is the key mechanism to change the etch selectivity of Si3N4 over SiO2.

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