Active CMOS-MEMS AFM-like conductive probes for field-emission assisted nano-scale fabrication

In this paper, a method of fabricating active CMOS-MEMS AFM-like conductive probes with nanometer-sized probe tips for Tip-directed Field-emission Assisted Nanofabrication (TFAN) is reported. We envision an approach using tip-directed chemical vapor deposition (CVD) for the deposition of Si nanowires (SNWs), using field-emitted electrons to locally crack adsorbed precursors (silane/disilane) through direct momentum transfer. This approach will enable control of nanowire geometry during fabrication. The designed active probe consists of three key parts: a thermal bimorph structure actuator, a capacitive sensor and a field emission (FE) probe tip. Unlike the past Spindt process for FE tip fabrication, a single-step probe tip fabrication process on CMOS-MEMS chips is introduced via electron-beam lithography and evaporation technique using PMMA as resist. The mechanism and key growth conditions for Spindt-type tip formation are investigated.