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 photoresist used in lithographic patterning.
Synonyms: BHF; Buffered HF
Application: Buffered oxide etchant (BOE) 6:1 with surfactant may be used in the oxide removal of AlGaN/GaN-based high electron mobility transistors for gate photolithography. It may also be used in a buffer oxide etchant method for the fabrication of micro biochip.