“…The long needles were formed in an Oxford Instruments System 100 fitted with a Cobra300 ICP source. A cryogenic etch 47,48,[56][57][58] was used as follows: SF 6 (60 sccm), O 2 (10 sccm), 10 mTorr pressure, 800 W ICP power, 6 W RIE power, À110 1C electrode, with 10 Torr He applied to the backside of the wafer for effective cooling, 30 min etching time. These long needles are some of the longest bSi features reported to date.…”