High rate etching of AlN using BCl3/Cl2/Ar inductively coupled plasma

Inductively-coupled-plasma reactive ion etching of AlN was investigated using BCl3/Cl2/Ar gas chemistry. AlN etch rates were studied as a function of substrate bias voltage (−150 to −400 V), ICP coil power (200–900 W) and chamber pressure (2–10 mT). Using an electroplated Ni mask, up to 50 μm deep AlN structures were etched. This is the first demonstration of deep etching of AlN at high etch rates using inductively-coupled-plasma. The results reported in this study can be used for bulk micro-machining AlN substrates.