Using Ultrathin Parylene Films as an Organic Gate Insulator in Nanowire Field-Effect Transistors

Area of Science:

• Materials Science
• Nanotechnology
• Electronics Engineering

Background:

• Traditional gate insulators in nanowire transistors often require high-temperature processing.
• Atomic layer deposition (ALD) of oxides faces limitations with surface treatments on nanowires.

Purpose of the Study:

• To develop and characterize nanowire field-effect transistors utilizing ultrathin parylene as a polymer gate insulator.
• To explore parylene's suitability as a low-temperature alternative to oxide insulators for nanoscale devices.

Main Methods:

• Development of a custom gas-phase deposition system for parylene.
• Fabrication of Ω-gate and gate-all-around nanowire field-effect transistor structures.
• Characterization of device performance, including subthreshold swing and on/off ratios.

Main Results:

• Achieved functional Ω-gate and gate-all-around structures with conformal parylene coating.
• Demonstrated excellent device performance: subthreshold swings as low as 140 mV/dec and on/off ratios exceeding 10^3.
• Showcased parylene's ability to deposit over chemically treated surfaces, unlike ALD oxides.

Conclusions:

• Parylene is a viable ultrathin polymer insulator for nanoscale electronic devices, offering advantages in low-temperature processing and surface compatibility.
• The developed fabrication strategy for gate-all-around structures overcomes previous limitations.
• Parylene's biocompatibility suggests potential applications in nanobioelectronics.