Proceedings Article | 2 September 1998
KEYWORDS: Metals, Silicon, Chemical species, Scanning tunneling microscopy, Molecules, Semiconductors, Oxides, Microelectromechanical systems, Manufacturing, Silicon carbide
We discuss a novel deposition method that uses electric field and local probes to deposit materials from gas phase. Using gas-phase metal-organic precursors, semiconductors such as Si, GaAs, GaN, and SiC, metals such as Al, Cu, Mo, W, and Pt, and oxides such as SiO2, and Al2O3, and other insulators such as Si3N4 can be deposited. These precursor gases are carried over the local tip area where relatively large electric fields (106 V/cm: field emission mode) are generated by applying a few volts to the probe. In the tip region, the electric field decomposes the precursor molecules and deposits the desired material over the substrate. By choosing the tip to substrate polarity appropriately, deposition over the tip is avoided. The rest of the decomposed precursor molecule remains in the gas phase and is carried away by the carrier neutral gas. A novel approach, that involves laterally vibrating the local probe, is used to achieve line-widths in the wide range of 100 angstroms to 10 micrometers . Local probes, depositing in parallel, efficiently cover large areas needed in integrated circuits. The speed of deposition by our proposed local probes is only limited by the rate of the material delivery by the carrier gas. In this novel approach the deposition chamber encloses a volume that is slightly larger than the local tip-substrate volume. Thus, the whole fabrication facility can be fabricated on silicon using bulk and surface micromachining used in micro-electro-mechanical systems (MEMS) technologies. All the valves, flow meters, pressure gauges and analysis tools can also be fabricated using MEMS technologies and constitute an integral part of the micro- fabrication facility.
