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) 10:1 can be used in the etching of titanium carbide, which can be used in microelectromechanical systems (MEMS). It can also be used in the etching of spin-on-dopant (SOD) for the development of conductor-insulator-conductor tunneling diodes. It can also be used to enhance the surface of fused quartz devices.