Buffered oxide etchant (BOE) 6:1 – Sigma-Aldrich

Synonyms
BHF, Buffered HF

Cas No.
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General Descriptions
BOE 6:1 is 6 parts by volume of 40% ammonium fluoride and 1 part by volume of 49% HF.
Buffered oxide etchant (BOE) is a wet etchant used in microfabrication. Its primary use is in etching thin films of silicon dioxide (SiO2) or silicon nitride (Si3N4). It is a mixture of a buffering agent, such as ammonium fluoride (NH4F), and hydrofluoric acid (HF). Concentrated HF etches silicon dioxide too quickly for good process control and also peels the photoresist used in lithographic patterning.

Application
Buffered oxide etchant (BOE) 6:1 can be used in the oxide removal of AlGaN/GaN-based high electron mobility transistors for gate photolithography. It can be used in a buffer oxide etchant method for the fabrication of a micro biochip.