Suspended silicon nanowires work after furnace-free fabrication
A peer-reviewed fabrication study made suspended silicon nanowires without high-temperature furnace steps and then demonstrated electrical operation. Temporary chromium protection preserved the wire during plasma etching. Transistor and hydrogen-sensing tests followed, showing laboratory function after a cooler process; commercial sensor durability and manufacturing yield across whole wafers remain unqualified.
Science··Midday
Chromium protection preserves a released wire
A peer-reviewed laboratory study made silicon wires anchored at both ends and suspended above the substrate, omitting high-temperature furnace steps. A temporary chromium coating protected a nanoscale silicon preform during deep plasma etching, which released the wire from underneath. The protective layers were then removed. The highest process temperature was a 180-degree polymer bake used in lithography; conventional high-temperature oxidation and deposition were omitted. Both bulk silicon and silicon-on-insulator substrates were used.[1]
Suspended devices retain electrical function
Wires reached 50 nanometres in width, with length-to-width ratios up to 100 and array spacing of 5 micrometres. Each geometry was examined using 20 wires from 3 chips. Individual wires and parallel arrays conducted current linearly. Lateral control gates gave a transistor geometry approximately 40-fold current modulation at a threshold around 24 volts.[1]
Palladium coating enables a hydrogen response
A nominal 2-nanometre palladium coating enabled a pronounced current drop during hydrogen exposure, followed by recovery after removal. The hydrogen response appeared in roughly 20–30 seconds; recovery required 200–250 seconds; calculated maximum electrical power was 6.7 nanowatts. These gas-flow laboratory tests did not establish commercial selectivity, long-term durability or full-wafer manufacturing yield.[1]
