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The Nanoscience Centre

Cambridge University nanofabrication and characterisation facility

Studying at Cambridge

 

Bay 2 - Wet processing

Laminar Flow Acid Benches

Acid etching is available in our class 10 laminar flow benches. Rather than a conventional fume extraction hood these benches provide a constant downward stream of low velocity hepa filtered air.

Hydrofluoric acid (HF) etches.

We use buffered oxide etch (BOE) or buffered hydrofluoric etch (BHF) as a wet etchant for micro-fabrication in a dedicated laminar flow cabinet. Used for etching thin films of silicon dioxide (SiO2) or silicon nitride (Si3N4). The most commonly used is a 7% BHF to remove the native oxide layer before metallisation.

Other etches.

Chrome etch CR75  (ammonium ceric nitrate and perchloric acid) is used for mask making. Gold etch GE6 (Potassium iodide / Iodine) and Piranha etch  (hydrogen peroxide and sulphuric acid) are normally used for the removal of organic residues.

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Veeco Dektak 6M Stylus Surface Profilometer

The Dektak surface profilometer is capable of measuring surface topography features to below 100Å and surface roughness in the nanometer range. Currently fitted with a 12.5μm diameter high aspect ratio diamond stylus.

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